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MCQ Questions for Class 10 Science Chapter 13 Magnetic Effects of Electric Current

Magnetic Effects of Electric Current Class 10 MCQ Questions With Answers

Question 1.

Choose the incorrect statement from the following regarding magnetic lines of field :

(A) The direction of magnetic field at a point is taken to be the direction in which the north pole of a magnetic compass needle points.
(B) Magnetic field lines are closed curves.
(C) If magnetic field lines are parallel and equidistant, they represent zero field strength.
(D) Relative strength of magnetic field is shown by the degree of closeness of the field lines. JJ
Answer:
(C) If magnetic field lines are parallel and equidistant, they represent zero field strength.

Explanation:
Magnetic field lines appear parallel when they are far from the magnet. But this does not mean that field strength is zero. No field line would be present where field strength becomes zero.

Question 2.

Which of the following correctly describes the magnetic field near a long straight current carrying wire?

(A) The field consists of straight lines perpendicular to the wire.
(B) The field consists of straight lines parallel to the wire.
(C) The field consists of radial lines originating from the wire.
(D) The field consists of concentric circles centered on the wire.
Answer:
(D) The field consists of concentric circles centered on the wire.

Explanation:
The field consists of concentric circles centered on the wire. On applying right-hand thumb rule, we find the direction of magnetic field. The field is in the form of concentric circles centered on the wire carrying current.

Question 3.

A constant current flowing in a horizontal wire in the plane of the paper from East to West is shown in Figure. The direction of magnetic field at a point will be from North to South :

(A) directly above the wire.
(B) directly below the wire.
(C) at a point located in the plane of the paper, on the north side of the wire.
(D) at a point located in the plane of the paper, on the south side of the wire.
Answer:
(B) directly below the wire.

Explanation:
Line WE shows a straight conductor through which current is moving from E to W. When seen from east, the magnetic field lines appear in clockwise direction, i.e. S to N above the wire and N to S below the wire. This is in accordance with right hand thumb rule.

Question 4.

If the key in the arrangement in the given Figure, is taken out (the circuit is made open) and magnetic field lines are drawn over the horizontal plane ABCD, the lines are:

(A) concentric circles.
(B) lliptical in shape.
(C) straight lines parallel to each other.
(D) concentric circles near the point O but of elliptical shapes as we go away from it.
Answer:
(C) straight lines parallel to each other.

Explanation:
When the key is taken out, the circuit is open, no current flows and no magnetic field due to current carrying conductor. There exists only earth’s magnetic field which will exhibit straight lines parallel to each other.

Question 5.

For a current in a long straight solenoid N- and S-poles are created at the two ends. Among the following statements, the incorrect statement is :

(A) The field lines inside the solenoid are in the form of straight lines which indicates that the magnetic field is the same at all points inside the solenoid.
(B) The strong magnetic field produced inside the solenoid can be used to magnetise a piece of magnetic material like soft iron, when placed inside the coil.
(C) The pattern of the magnetic field associated with the solenoid is different from the pattern of the magnetic field around a bar magnet.
(D) The N and S-poles exchange position when the direction of current through the solenoid is reversed.
Answer:
(C) The pattern of the magnetic field associated with the solenoid is different from the pattern of the magnetic field around a bar magnet.
Explanation: A solenoid behaves like a bar magnet. Hence, the pattern of the magnetic field associated with the solenoid is same as the pattern of the magnetic field around a bar magnet.

Question 6.

The strength of magnetic field inside a long current carrying straight solenoid is :

(A) more at the ends than at the centre
(B) minimum in the middle
(C) same at all points
(D) found to increase from one end to the other
Answer:
(C) same at all points

Explanation:
Magnetic field lines are straight and parallel inside the solenoid. This indicates a same magnetic field. Hence, inside the solenoid, the magnetic field is same throughout.

Question 7.

Which of the following property of a proton can change while it moves freely in a magnetic field? (There may be more than one correct answer.)

(A) Mass
(B) Speed
(C) Velocity
(D) Momentum
Answer:
(C) Velocity (D) Momentum

Explanation:
When a proton enters a magnetic field, it starts moving on a circular path. Because of its movement along a circular path it attains angular momentum. We know that momentum is a product of mass and velocity. Therefore velocity and mass of a proton change when it enters a magnetic field.

Question 8.

A positively-charged particle (alpha – particle pro-jected towards west is deflected towards north by a magnetic field. The direction of magnetic field is

(A) towards south.
(B) towards east.
(C) downward.
(D) upward.
Answer:
(D) upward.

Explanation:
In accordance with Fleming’s Left-Hand Rule, the direction of magnetic field is vertically upward.

Question 9.

The phenomenon of electro-magnetic induction is :

(A) the process of charging a body.
(B) the process of generating magnetic field due to a current passing through a coil.
(C) producing induced current in a coil due to relative motion between a magnet and the coil.
(D) the process of rotating a coil of an electric motor.
Answer:
(C) producing induced current in a coil due to relative motion between a magnet and the coil.
Explanation: In electro-magnetic induction phenomenon, an induced current begins to flow in a coil whenever there is a change in magnetic field in and around a coil.

Question 10.

The essential difference between an AC generator and a DC generator is that:

(A) AC generator has an electro-magnet while a DC generator has permanent magnet.
(B) DC generator will generate a higher voltage.
(C) AC generator will generate a higher voltage.
(D) AC generator has slip rings while the DC generator has a commutator.
Answer:
(D) AC generator has slip rings while the DC generator has a commutator.

Explanation:
AC generator has slip rings while the DC generator has a commutator.

Question 11.

Choose the correct option. A rectangular coil of copper wires is rotated in a magnetic field. The direction of the induced current changes once in each:

(A) two revolutions.
(B) one revolution.
(C) half revolution.
(D) one-fourth revolution.
Answer:
(C) half revolution.

Explanation:
When a rectangular coil of copper wire is rotated in a magnetic field, the direction of the induced current changes once in each half revolution.

Question 12.

Choose the incorrect statement:

(A) Fleming’s right-hand rule is a simple rule to know the direction of induced current.
(B) The right-hand thumb rule is used to find the direction of magnetic fields due to current-carrying conductors.
(C) The difference between the direct and alternating currents is that the direct current always flows in one direction, whereas the alternating current reverses its direction periodically.
(D) In India, the AC changes direction after every 1/50 second.
Answer:
(D) In India, the AC changes direction after every 1/50 second.

Explanation:
In India, the AC changes direction after every 1/100 second.

Question 13.

At the time of short circuit, the current in the circuit:

(A) reduces substantially
(B) does not change
(C) increases heavily
(D) vary continuously
Answer:
(C) increases heavily

Explanation:
At the time of short circuiting the live wire and the neutral wire come into direct contact. As a result, the current in the circuit increases abruptly.

Question 14.

The most important safety method used for protecting home appliances from short circuiting or overloading is :

(A) Earthing
(B) use of fuse
(C) use of stabilisers
(D) use of electric meter A
Answer:
(B) use of fuse

Explanation:
A fuse is a short length of wire designed to melt in the event of excessive current flow.

Assertion and Reason Based MCQs

Directions : In the following questions, A statement of Assertion (A) is followed by a statement of Reason (R). Mark the correct choice as.
(A) Both A and R are true and R is the correct explanation of A.
(B) Both A and R are true but R is NOT the correct explanation of A.
(C) A is true but R is false.
(D) A is false and R is true.

Question 1.

Assertion (A): Two bar magnets attract when they are brought near to each other with the same pole.
Reason (R): Unlike poles will attract each other.

Answer:
(D) A is false and R is true.

Explanation:
Two bar magnets repel when same poles face each other. Opposite poles attract each other

Question 2.

Assertion (A): Magnetic field lines never intersect.
Reason (R): At a particular point magnetic field has only one direction.

Answer:
(A) Both A and R are true and R is the correct explanation of A.

Explanation:
Magnetic field lines never intersect each other as for two lines to intersect, there must be two north directions at a point, which is not possible.

Question 3.

Assertion (A): In Fleming’s Left Hand Rule, the direction of magnetic field, force and current are mutually perpendicular.
Reason (R): Fleming’s Left hand Rule is applied to measure the induced current.

Answer:
(C) A is true but R is false.

Explanation:
It is used to find the direction of force in a current carrying conductor in the presence of magnetic field.

Question 4.

Assertion (A): An alpha particle placed in a magnetic field will not experience any force, if it moves in the magnetic field parallel to field lines.
Reason (R): The force is zero if current and field are in the same direction.

Answer:
(A) Both A and R are true and R is the correct explanation of A.

Explanation:
An alpha particle placed in a magnetic field will not experience any force, if it moves in the magnetic field parallel to field lines. It is because, the force is zero if current and field is in the same direction.

Question 5.

Assertion (A): Safety fuses are made up of materials having a low melting point.
Reason (R): Safety fuses should be resistant to electric current.

Answer:
(C) A is true but R is false.

Explanation:
Safety fuses are made up of materials having a low melting point so that when excess current flow through the circuit,
the fuse melts breaking the circuit and thus prevents appliances.

Question 6.

Assertion (A): Copper is used to make electric wires.
Reason (R): Copper has very low electrical resistance.

Answer:
(A) Both A and R are true and R is the correct explanation of A.

Explanation:
The low electrical resistance of copper makes it a good conductor for electricity.

Question 7.

Assertion (A): When two bulbs are operated on same voltage supply, having power 60 W and 100 W then 100 W bulb has less resistance than 60 W. Reason (R): The power of the bulb is directly proportional to the square of the voltage.

Answer:
(B) Both A and R are true but R is NOT the correct explanation of A.

Explanation:
Since, power (P) Hence, 100 W bulb has less resistance.

Case-Based MCQs

Attempt any 4 sub-parts from each question. Each sub-part carries 1 mark.
I. Read the following passage and answer any four questions from Question 1. to Question 5.
A solenoid is a long helical coil of wire through which a current is run in order to create a magnetic field. The magnetic field of the solenoid is the superposition of the fields due to the current through each coil. It is nearly uniform inside the solenoid and close to zero outside and is similar to the field of a bar magnet having a north pole at one end and a south pole at the other depending upon the direction of current flow.
The magnetic field produced in the solenoid is dependent on a few factors such as, the current in the coil, number of turns per unit length etc. The following graph is obtained by a researcher while doing an experiment to see the variation of the magnetic field with respect to the current in the solenoid.
The unit of magnetic field as given in the graph attached is in mili-Tesla (mT) and the current is given in Ampere.

Question 1.

What type of energy conversion is observed in a linear solenoid?

(A) Mechanical to Magnetic
(B) Electrical to Magnetic
(C) Electrical to Mechanical
(D) Magnetic to Mechanical
Answer:
(B) Electrical to Magnetic

Explanation:
In a solenoid, the current flowing through the circuit generates its own magnetic field. Hence the electrical energy of the circuit is converted to magnetic field.

Question 2.

What will happen if a soft iron bar is placed inside the solenoid?

(A) The bar will be electrocuted resulting in short- circuit.
(B) The bar will be magnetised as long as there is current in the circuit.
(C) The bar will be magnetised permanently.
(D) The bar will not be affected by any meAnswer:
Answer:
(B) The bar will be magnetised as long as there is current in the circuit.

Explanation:
The magnetic field produced by the solenoid will be reinforced by the iron bar and it will be magnetised as long as there is current in the circuit.

Question 3.

The magnetic field lines produced inside the solenoid are similar to that of… A

(A) a bar magnet
(B) a straight current carrying conductor
(C) a circular current carrying loop
(D) electromagnet of any shape
Answer:
(A) a bar magnet

Explanation:
Solenoids mimic bar magnets. The magnetic field of a solenoid are similar to that of a bar magnet and just like a bar magnet a solenoid also has north and south poles.

Question 4.

After analysing the graph a student writes the following statements.

(A) The magnetic field produced by the solenoid is inversely proportional to the current.
(B) The magnetic field produced by the solenoid is directly proportional to the current.
(C) The magnetic field produced by the solenoid is directly proportional to square of the current.
(D) The magnetic field produced by the solenoid is independent of the current. Choose from the following which of the following would be the correct statement(s).

(A) Only IV
(B) I and III and IV
(C) I and II
(D) Only II
Answer:
(D) Only II

Explanation:
As can be seen from the graph the magnetic field is increasing linearly with current. Therefore, the current is directly proportional to the magnetic field.

Question 5.

From the graph deduce which of the following statements is correct ?

(A) For a current of 0.8A the magnetic field is 13 mT
(B) For larger currents, the magnetic field increases non-linearly.
(C) For a current of 0.8A the magnetic field is 1.3 mT
(D) There is not enough information to find the magnetic field corresponding to 0.8A current.
Answer:
(A) For a current of 0.8A the magnetic field is 13 mT

Explanation:
From the above graph we can see that 0.8 A corresponds to 13 mT magnetic field.

II. Study the given diagram and answer any of the four questions form Question 1. to Question 5.
In the given diagram, two coils of insulated copper wire are wound over a nonconducting cylinder as shown. Coil P has larger number of turns.

Question 1.

A momentary deflection is shown by the galvanometer, when:

(A) Key K is open
(B) Key K is closed
(C) In both the situations
(D) In neither of the case.
Answer:
(C) In both the situations

Explanation:
Momentary deflection is seen in both the cases. When the key K is open, deflection is shown by the galvanometer and when it is closed, a momentary deflection is seen in opposite direction.

Question 2.

Which phenomenon is involved in it ?

(A) Electromagnetic induction
(B) Magnetism
(C) Electromagnetism
(D) None of these
Answer:
(A) Electromagnetic induction

Explanation:
Electromagnetic induction is the process by which a changing magnetic field in a conductor induces current in another conductor.

Question 3.

In above phenomenon, the current is induced in another conductor,

(A) By changing magnetic field
(B) By increasing the strength of current
(C) By decreasing the strength of the current
(D) By using extra wire.
Answer:
(A) By changing magnetic field

Explanation:
Electromagnetic current is induced in another conductor by changing the magnetic field.

Question 4.

The rule which helps us to know direction of induced current:

(A) Flemings right hand rule
(B) Flemings left hand rule
(C) Electro magnetic induction
(D) Faraday’s Law
Answer:
(A) Flemings right hand rule

Explanation:
Flemings right hand rule helps us to know the direction of induced current.

Question 5.

Flemings right hand rule explains:

(A) Direction of magnetic field
(B) Direction of motion of conductor
(C) Only (a)
(D) Both (a) and (b)
Answer:
(D) Both (a) and (b)

Explanation:
In Fleming’s Right Hand Rule the first three fingers of the right hand are mutually perpendicular to each other such that the forefinger gives the direction of magnetic field and the thumb points in the direction of the motion of a conductor then, the middle finger will give the direction of the induced current.

III. Read the following passage and answer any four questions from Question 1. to Question 5.
A student fixes a sheet of white paper on a drawing board. He places a bar magnet in the centre of it. He sprinkles some iron filings uniformly around the bar magnet. Then he taps the board gently and observes that the iron filings arrange themselves in a particular pattern.

Question 1.

Why do the iron fillings arrange themselves in a particular pattern ?

(A) Due to external force applied on the magnet.
(B) Due to force exerted by the magnet outside the magnetic field.
(C) Due to the force exerted by magnet within its magnetic field.
(D) Due to pressure of magnetic field.
Answer:
(C) Due to the force exerted by magnet within its magnetic field.

Explanation:
It is due to the force exerted by the magnet within its magnetic field.

Question 2.

What do the lines along which the iron fillings align represent ?

(A) North pole and south pole of the magnet
(B) Strength of the magnet
(C) Magnetic field lines
(D) Gravitational force.
Answer:
(C) Magnetic field lines

Explanation:
The lines represent magnetic field lines.

Question 3.

What does the crowding of iron filings at the end of the magnet indicate?

(A) Magnetic field is strongest near the poles of the magnet.
(B) Magnetic field is weakest near the poles of the magnet.
(C) There is no significant magnetic field at the poles of the magnet.
(D) The significance of polarity
Answer:
(A) Magnetic field is strongest near the poles of the magnet.

Explanation:
Crowding of iron filings at the ends of the magnet indicates that the magnetic field is strongest near the poles of the magnet.

Question 4.

The closer field lines indicate:

(A) Magnetic field in that region is weak
(B) Magnetic field in that region is strong.
(C) Magnetic field in that region is zero.
(D) North and South poles are closer.
Answer:
(B) Magnetic field in that region is strong.

Explanation:
The strength of magnetic field is indicated by the closeness of the field lines. Closer the lines, more will be the strength and farther the lines, lesser will be the field strength.

Question 5.

What is SI unit of magnetic field:

(A) Pascal
(B) Nm2
(C) Tesla
(D) No unit
Answer:
(C) Tesla

Explanation:
Tesla is the SI unit of magnetic field.

MCQ Questions for Class 10 Science with Answers

MCQ Questions for Class 10 Science Chapter 13 Magnetic Effects of Electric Current Read More »

MCQ Questions for Class 10 Science Chapter 12 Electricity

MCQ Questions / Prasanna

Electricity Class 10 MCQ Questions With Answers

Question 1.

A cylindrical conductor of length T and uniform area of cross section A’ has resistance ‘R’. The area of cross section of another conductor of same material and same resistance but of length ’21’ is

(A) $\frac{A}{2}$
(B) $\frac{3 A}{2}$
(C) 2A
(D) 3A
Answer:
(C) 2A

Explanation:
Resistivity of the conductor in the first case, p = $\frac{\mathrm{RA}}{l}$
Resistivity of the conductor in second case, p = $\rho=\frac{\mathrm{RA}^{\prime}}{2 l}$
Since, both conductors are of same material and are at same temperature, so the resistivity of both the conductors will be same.
Therefore, from equations, (i) and (ii), we have :
$\Rightarrow \frac{\mathrm{RA}}{l}=\frac{\mathrm{RA}^{\prime}}{2 l}$
=>A’ = 2A

Question 2.

The maximum resistance which can be made using four resistor each of resistance $\frac{1}{2} Ω$ is

(A) 2 Ω
(B) IΩ
(C) 2.5 Ω
(D) 8 Ω
Answer:
(A) 2 Ω

Explanation:
Maximum resistance in series = 41 x l/2 = 2 Ohm.

Question 3.

When a 4V battery is connected across an unknown resistor there is a current of 100 mA in the circuit. The value of the resistance of the resistor is:

(A) 4 Ω
(B) 40 Ω
(C) 400 Ω
(D) 0.4 Ω
Answer:
(B) 40 Ω

Explanation:
V=IR, V = 4 V, I = 100 mA = 0.1 A
Hence, R=$=\frac{V}{l}$=$\frac{4}{0.1}$ = 40Ω

Question 4.

Unit of electric power may also be expressed as:

(A) Volt-ampere
(B) Kilowatt-hour
(C) Watt-second
(D) Joule-second JR[
Answer:
(A) Volt-ampere

Explanation:
Unit of electric power is volt- ampere.

Question 5.

A cell, a resistor, a key, and ammeter are arranged as shown in the circuit diagrams given below. The current recorded in the ammeter will be:

(A) maximum in (i).
(B) maximum in (ii).
(C) maximum in (iii).
(D) the same in all the cases.

Answer:
(D) the same in all the cases.

Explanation:
In series connections, the order of elements in the circuit will not affect the amount of current flowing in the circuit.

Question 6.

Electrical resistivity of a given metallic wire depends upon

(A) its length.
(B) its thickness.
(C) its shape.
(D) nature of the material.
Answer:
(D) nature of the material.

Explanation:
The resistivity of a material is constant for a particular material at a constant temperature. It only depends on the temperature. Resistivity of material does not depend on length, thickness, and shape of the A material.

Question 7.

A current of A is drawn by a filament of an electric bulb. Number of electrons passing through a cross section of the filament in 16 seconds would be where, e = 1.6 x 10^-19 C

(A) 10²⁰
(B) 10²⁰
(C) 10¹⁸
(D) 10¹⁹
Answer:
(A) 10²⁰

Explanation:
Given, 1=1 Amp.
t = 16 s
Asl = $\frac{Q}{t}$ = $\frac{n e}{t}$
n = $\frac{\left(1^{t} \times T\right)^{t}}{e}$ = $\frac{n e}{t}$ $\left(1^{t} \times \mathrm{T}\right)^{t}$ = $\frac{1 \times 16}{1.6 \times 10^{-19}}$

n = 10²⁰

Question 8.

The resistivity does not change if :

(A) the material is changed.
(B) the temperature is changed.
(C) the shape of the resistor is changed.
(D) both material and temperature are changed.
Answer:
(C) the shape of the resistor is changed.

Explanation:
Resistivity always varies with change in temperature, nature of material. But resistivity cannot be change in any shape of conductor.

Question 9.

Two bulbs of 100 W and 40 W are connected in series. The current through the 100 W bulb is 1 A. The current through the 40 W bulb will be:

(A) 0.4 A
(B) 0.6 A
(C) 0.8 A
(D) 1 A
Answer:
(D) 1 A

Explanation:
In a series connection, the current through each device remains the same. Therefore, the current through the 40 W bulb will also be 1 A.

Question 10.

What is the maximum resistance which can be made using five resistors each of $\frac{1}{5}$Ω ?

(A) $\frac{1}{5}$Ω
(B) 10Ω
(C) 5Ω
(D) 1 Ω
Answer:
(D) 1 Ω

Explanation:
The highest resistance is always given by connecting the resistors in series. Here, the highest resistance would be 5 x – =1 Ω. 5 Therefore, the maximum resistance is 1 ohm.

Question 11.

What is the minimum resistance which can be made using five resistors each of $\frac{1}{5}$Ω ?

(A) $\frac{1}{5}$Ω
(B) $\frac{1}{25}$Ω
(C) $\frac{1}{10}$Ω
(D) 25 Ω
Answer:
(B) $\frac{1}{25}$Ω

Explanation:
Minimum resistance is obtained when resistors are connected in parallel combination. Thus, equivalent resistance obtained by connecting five resistors of resistance $\frac{1}{5} \Omega$ each, parallel to each other :
$\frac{1}{R}=\frac{1}{1_{5}}+\frac{1}{1_{5}}+\frac{1}{1_{5}}+\frac{1}{1_{5}}+\frac{1}{1 / 5} \Rightarrow \frac{1}{R}=\frac{5}{1 / 5}$

=> $\frac{1}{R}$ = $\frac{25}{1}$
=> R =(B) $\frac{1}{25}$Ω

Question 12.

Which of the following represents voltage?

(A) $\frac{\text { Work done }}{\text { Current } \times \text { Time }}$
(B) Work done × Charge
(C) $\frac{\text { Work done } \times \text { Time }}{\text { Current }}$
(D) $\frac{\text { Work done } \times \text { Charge }}{\text { Time }}$

Explanation:
As we know that,
Work done = Charge x Potential difference =>Work done = (Current x Time) x Potential Difference [∴ Charge = Current x time]
=> Potential difference $=\frac{\text { Work done }}{\text { Current } \times \text { Time }}$

Question 13.

If the current through a resistor is increased by 100% (assume that temperature remains unchanged), the increase in power dissipated will be

(A) 100%
(B) 200%
(C) 300%
(D) 400%
Answer:
(C) 300%

Explanation:
If is current and R is resistance then,
Power, P =I₂R
Power in first case, P₁ = I₂R 100% increase in current means that current becomes 21
Power in second case, P2 = (2I)₂R = 4I₂R
Now, increase in dissipated power = P2 – P1
= 4I₂R – I₂R = 3I2R
Percentage increase in dissipated power = $\frac{3 P_{1}}{P_{1}} \times 100$ = 300%

Question 14.

In an electrical circuit three incandescent bulbs A, B, and C of rating 40 W, 60 W, and 100 W, respec¬tively are connected in parallel to an electric source. Which of the following is likely to happen regard¬ing their brightness?

(A) Brightness of all the bulbs will be the same.
(B) Brightness of bulb A will be the maximum.
(C) Brightness of bulb B will be more than that of A.
(D) Brightness of bulb C will be less than that of B.
Answer:
(C) Brightness of bulb B will be more than that of A.

Explanation:
We know that power is defined as rate of doing work. A bulb consumes electric energy and produces heat and light. Now, bulb with more power rating will produce more heat and light or we can say that power rating of bulb is directly proportional to the brightness produced by bulb. Therefore, brightness of bulb B with power rating 60 W will be more than the brightness of bulb A having power rating as 40 W.

Question 15.

An electric kettle consumes 1 kW of electric power when operated at 220 V. A fuse wire of what rating must be used for it?

(A) 1 A
(B) 2 A
(C) 4 A
(D) 5 A
Answer:
(D) 5 A

Explanation:
Given that,
power = P = 1 kW = 1000 W
Voltage = V = 220
N0w,I = $\frac{P}{V}$ = $\frac{1000}{220}$ = 4.5A Now rating of fuse wire must be slightly greater than 4.5 A, that is, 5 A.

Assertion and Reason Based MCQs

Question 1.

Assertion (A): A conductor has + 3.2 x 10₁₉ C charge.
Reason (R): Conductor has gained 2 electrons.

Answer:
(C) A is true but R is false.

Explanation:
Conductor has positive charge, so it has lost two electrons.

Question 2.

Assertion (A): The resistivity of conductor increases with the increasing of temperature.
Reason (R): The resistivity is the reciprocal of the conductivity.

Answer:
(B) Both A and R are true but R is NOT the correct explanation of A.

Explanation:
The resistivity of the conductors is directly proportional to temperature.

Question 3.

Assertion (A): Bending a wire does not affect electrical resistance.
Reason (R): Resistance of wire is proportional to resistivity of material.

Answer:
(A) Both A and R are true and R is the correct explanation of A.

Explanation:
Resistance of wire R = p $\left(\frac{l}{A}\right)$ Where p is resistivity of material which does not depend on the geometry of wire. Since when wire is bent its, resistivity, length and area of cross-section do not change, therefore resistance of wire also remains same.

Question 4.

Assertion (A): Two resistance having value R each. Their equivalent resistance is$\frac{R}{2}$.
Reason (R): Given Resistances are connected in parallel.

Answer:
(A) Both A and R are true and R is the correct explanation of A.

Explanation:
When two resistances R1 and R2 connected in parallel than their equivalent resistance will be R = $\frac{R_{1} R_{2}}{R_{1}+R_{2}}$

Question 5.

Assertion (A): Alloys are commonly used in electrical heating devices like electric iron and heater.
Reason (R): Resistivity of an alloy is generally higher than that of its constituent metals but the alloys have low melting points then their constituent metals.

Answer:
(C) A is true but R is false.

Explanation:
Alloys have high resistivity and high melting point as compared to pure metals. So alloys cannot easily bum or oxidize at higher temperature. Now as we want higher temperature in heating devices so we use alloys in heating devices.

Question 6.

Assertion (A): In a simple battery circuit the point of lowest potential is positive terminal of the battery.
Reason (R): The current flows towards the point of the lower potential as it flows in such a circuit from the positive to the negative terminal.

Answer:
(D) A is false and R is true.

Explanation:
In a simple battery circuit, the point of lowest potential is the negative terminal of the battery and the current flows from higher potential to lower potential.

Question 7.

Assertion (A): Electric appliances with metallic body have three connections, whereas an electric bulb has a two pin connection.
Reason (R): Three pin connections reduce heating of connecting wires.

Answer:
(C) A is true but R is false.

Explanation:
The metallic body of an electrical appliances is connected to the third pin which is connected to the earth. This is a safety precaution and avoids eventual electric shock. By doing this the extra charge flowing through the metallic body is passed to earth and avoid shocks. There is nothing such as reducing of the heating of connecting wires by three pin connections.

Question 8.

Assertion (A): The electric bulbs glow immediately when switch is ON.
Reason (R): The drift velocity of electrons in a metallic wire is very high.

Answer:
(A) Both A and R are true and R is the correct explanation of A.

Explanation:
In a conductor there are large numbers of free electrons. When we close the circuit, the electric field is established instantly with the speed of electromagnetic wave which causes electron drift at every portion of the circuit. Due to which the current is set up in the entire circuit instantly. The current which is set up does not wait for the electrons flow from one end of the conductor to another end. It is due to this, the bulb glows immediately when switch is ON.

Question 9.

Assertion (A): Copper is used to make electric wires.
Reason (R): Copper has very low electrical resistance.

Answer:
(A) Both A and R are true and R is the correct explanation of A.

Explanation:
A low electrical resistance of copper makes it a good electric conductor. So, it is used to make electric wires.

Question 10.

Assertion (A): Silver is not used to make electric wires.
Reason (R): Silver is a bad conductor.

Answer:
(C) A is true but R is false.

Explanation:
Silver is a good conductor of electricity but it is not used to make electric wires because it is expensive.

Case- Based MCQs

Attempt any 4 sub-parts from each question. Each sub-part carries 1 mark.
I. Read the passage and answer any four questions from Question 1. to Question 5.
Three resistors of 5 Si, 10 Q and 15 Q are connected in series and the combination is connected to the battery of 30 V. Ammeter and voltmeter are connected in the circuit.

Question 1.

Which of the following is the correct circuit diagram to connect all the devices in proper correct order.

Answer:

Expianation:
The correct circuit diagram is:

Question 2.

How much is the total resistance?

(A) 30Ω
(B) 20Ω
(C) $\frac{11}{30} \Omega$
(D) $\frac{30}{11} \Omega$
Answer:
(A) 30Ω

Explanation:
R = R1 + R2 + R3 = 30Ω

Question 3.

Two students perform experiments on two given resistors R₁ and R₂ and plot the following V-I graphs. If R₁ > R₂ which of the diagrams correctly

Answer:

Explanation:
Diagram 1 is correct as R, is large so the slope of V-I graph (V/I) is greater in diagram and is correctly represented as R₁.

Question 4.

The device used to measure the current:

(A) Ammeter
(B) Galvanometer
(C) Voltmeter
(D) None of these
Answer:
(A) Ammeter

Explanation:
Ammeter is used to measure the current.

Question 5.

Which of the following is connected in series in circuit:

(A) Ammeter
(B) Voltmeter
(C) Both of these
(D) None of these
Answer:
(A) Ammeter

Explanation:
Ammeter is used to measure the current. It is connected in series in the circuit.

III. Study the given table and answer any four questions from Question 1. to Question 5.

	Material	Resistivity (Ω m)
Conductors	Silver	1.60 x 10^-8
	Copper	1.62 x 10^-8
	Aluminium	2.63 x 10^-8
	Tungsten	5.20 x 10^-8
	Nickel	6.84 x 10^-8
	Iron	10.0 x l0^-8
	Chromium	12.9 x 10^-8
	Mercury	94.0 x 10^-8
	Manganese	1.84 x 10^-6
Alloys	Constantan	49 x l0^-6
	[alloy of Cu and Ni]
	Manganin [alloy of Cu, Mn and Ni]	44 x 10^-6
	Nichrome [alloy of Ni, Cr, Mn and Fe]	100 x 10^-6

Question 1.

Which is a better conductor ?

(A) Chromium
(B) Nickel
(C) Mercury
(D) Iron
Answer:
(B) Nickel

Explanation:
Nickel is better conductor because its resistivity value is lower than others.

Question 2.

Element used to make heating element of electric geyser:

(A) Iron
(B) Silver
(C) Nichrome
(D) Tungsten
Answer:
(C) Nichrome

Explanation:
Nichrome is used to make the heating element of an electric geyser.

Question 3.

Element used to make filament of incandescent bulb:

(A) Copper
(B) Silver
(C) Nichrome
(D) Tungsten
Answer:
(D) Tungsten

Explanation:
Tungsten is used to make filament of incandescent bulb.

Question 4.

What happens to resistance of a conductor when its area of cross section is increased?

(A) Resistance increases
(B) Resistance decreases
(C) No change
(C) Resistance doubles
Answer:
(B) Resistance decreases

Explanation:
Electrical resistance is directly proportional to the length (L) of the conductor and inversely proportional to the cross sectional area (A).

Question 5.

A given length of a wire is doubled and this process is repeated once again. The resistance of wire becomes:

(A) 1/4th of original resistance
(B) 16 times of original resistance
(C) Double the original resistance
(D) Half of original resistance
Answer:
(B) 16 times of original resistance

Explanation:
Let resistance of the wire be R. When the wire is doubled and the process is repeated then the length of the wire reduced by 1/4 times.

So, resistance = $\frac{\mathrm{R}}{4}$
The total resistance of the wire when the resistance are arranged in parallel,
$\frac{1}{R_{p}}=\frac{1}{\frac{R}{4}}+\frac{1}{\frac{R}{4}}+\frac{1}{\frac{R}{4}}+\frac{1}{\frac{R}{4}}+\frac{1}{\frac{R}{4}} \Rightarrow \frac{16}{R}$
$\frac{1}{R_{p}}=\frac{16}{R}$
The resistance of the wire reduced by 16 times

IV. Observe the following table and answer any four questions from Question 1. to Question 5. Electrical resistivities of some substances, at 20°C are given as follows:

Silver	1.60 x 10^-8Ω.m
Copper	1.62 x 10^-8Ω.m
Tungsten	5.2 x 10^-8Ω.m
Mercury	94 x 10^-8Ω.m
Iron	10 x 10^-8Ω.m
Nichrome	10 x 10^-6Ω.m

Question 1.

Which is a better conductor of electric current ?

(A) Silver
(B) Copper
(C) Tungsten
(D) Mercury
Answer:
(A) Silver

Explanation:
Silver is a better conductor because it has lower resistivity.

Question 2.

Which element will be used for electrical transmission lines ?

(A) Iron
(B) Copper
(C) Tungsten
(D) mercury
Answer:
(B) Copper

Explanation:
Copper, because it is economical and has low resistivity.

Question 3.

Nichrome is used in the heating elements of electric heating device because:

(A) It has high resistivity
(B) It does not oxidise readily at high temperature
(C) Both of the above
(D) None of the above
Answer:
(C) Both of the above

Explanation:
Nichrome as it has very high resistivity as it is an alloy, it does not oxidize readily at high temperature.

Question 4.

Series arrangement is not used for domestic circuits because:

(A) Current drawn is less
(B) Current drawn is more
(C) Neither of the above
(D) Both of the above
Answer:
(A) Current drawn is less

Explanation:
In series arrangement, same current will flow through all the appliances which is not required and the equivalent resistance becomes higher, hence the current drawn becomes less.

Question 5.

If the resistance is to be increased, then the resistors are to be increased in:

(A) Series
(B) Parallel
(C) Mixed arrangement
(D) None of the above
Answer:
(A) Series

Explanation:
The effective resistance in the series is the sum of individual resistances. So, the resistances should be connected in series in order to increase the effective resistance.

V. Based on the given diagram, answer any of the four questions form Question 1. to Question 5.
In the given circuit, connect a nichrome wire of length ‘L’ between points X and Y and note the ammeter reading.

Question 1.

When this experiment is repeated by inserting another nichrome wire of the same thickness but twice the length (2L), what changes are observed in the ammeter reading ?

(A) Ammeter reading will increase
(B) Ammeter reading will decrease
(C) Will show double the increase
(D) No change in ammeter reading
Answer:
(A) Ammeter reading will increase

Explanation:
The ammeter reading will decrease (becomes half). This is because with the increase in length, resistance of the circuit increases, hence current decreases.

Question 2.

State the changes that are observed in the ammeter reading if we double the area of cross section without changing the length in the above experiment.

(A) Ammeter reading will increase
(B) Ammeter reading will decrease
(C) Will decrease to half
(D) No change in ammeter reading
Answer:
(B) Ammeter reading will decrease

Explanation:
The ammeter reading will increase (becomes two times). This is because as area increases, resistance decreases and hence current increases.

Question 3.

In a circuit two resistors of 5Ω and 10 Ω are connected in series. Compare the current passing through the two resistors.

(A) 1 : 2
(B) 1 : 3
(C) 2 : 1
(D) 1 : 1
Answer:
(D) 1 : 1

Explanation:
In a series connection of resistors, same current passes through all the resistors. Hence, current will be same. Ratio of the currents will be 1:1.

Question 4.

The instrument used to measure current is ……..

(A) Ammeter
(B) Voltmeter
(C) Galvanometer
(D) manometer
Answer:
(A) Ammeter

Explanation:
Ammeter is used to measure current.

Question 5.

When nichrome and copper wire of same length and same radius are connected in series and current is passed through them. Which wire gets heated up more?

(A) Nichrome wire
(B) Copper wire
(C) Both will heat up at the same temperature
(D) None of the wire will get heated up.
Answer:
(A) Nichrome wire

Explanation:
In series combination current is same in nichrome and copper wires. Thus nichrome wire will produce more heat.

VI. Study the given circuit diagram and answer any of the four questions form Question 1. to Question 5. In this circuit, three identical bulbs B₁, B₂ and B₃are connected in parallel with a battery of 4.5 V.

Question 1.

What will happen to the other two bulbs if the bulb B₃ gets fused ?

(A) They will also stop glowing
(B) Other bulbs will glow with same brightness
(C) They will glow with low brightness
(D) They glow with more brightness
Answer:
(B) Other bulbs will glow with same brightness

Explanation:
Other bulbs will glow with same brightness

Question 2.

If the wattage of each bulb is 1.5 W, how much readings will the ammeter A show when all the three bulbs glow simultaneously.

(A) 1.0A
(B) 2A
(C) 1.5W
(D) None of the above
Answer:
(A) 1.0A

Explanation:
When the bulbs are in parallel, wattage will be added (4,5 W) and the ammeter reading would be,
I = p/v = $\frac{4.5}{4.5}$ = 1A

Question 3.

Find the total resistance of the circuit:

(A) 1.00
(B) 4.50
(C) 1.50
(D) 2.00
Answer:
(B) 4.50

Explanation:
Ammeter reading =l.OA
V = 4.5V
R = V/I
= 4.5 = 4.5 Ω

Question 4.

How many resistors of 88 W are connected in parallel to carry 10 A current on a 220 V line ?

(A) 2 resistors
(B) 1 resistors
(C) 3 resistors
(D) 4 resistors
Answer:
(D) 4 resistors

Explanation:
Equivalent resistance,
= $\frac{1}{R_{p}}$ = $\frac{n}{88}$
Rp = $\frac{88}{n}$
V = IR
R = $\frac{88}{n}$
$\frac{88}{n}$ = $\frac{220}{10}$
n = 4 resistors

Question 5.

Find the statement which does not justify parallel connection:

(A) The voltage of each component is same
(B) Overall resistance is lower than the resistance of single component
(C) Automobile headlight is connected in parallel
(D) There is a single path for the flow of electrons charge
Answer:
(D) There is a single path for the flow of electrons charge

Explanation:
There is path of flow of electron change through each resistor. So there are several path.

VII. Study the given passage and answer any of the four questions from Question 1. to Question 5.
Two conductors A and B of resistances 5 O and 10 C2 respectively are first joined in parallel and then in series. In each case the voltage applied is 20 V.

Question 1.

Which of these circuit diagram shows the correct connection when A and B are joined in parallel?

(D) none of these
Answer:

Explanation:
The diagram (A) correctly shows the combination of these conductors in each case.

Question 2.

In which combination will the voltage across the conductors A and B be the same ?

(A) Series arrangement
(B) Parallel arrangement
(C) Both of the above
(D) None of the above
Answer:
(B) Parallel arrangement

Explanation:
Voltage across A and B will be same in parallel arrangement.

Question 3.

In which arrangement will the current through A and B be the same ?

(A) Series arrangement
(B) Parallel arrangement
(C) Both of the above
(D) None of the above
Answer:
(A) Series arrangement

Explanation:
Current in A and B will be same in series arrangement.

Question 4.

Equivalent resistance in parallel combination is:

(A) 15 Ω
(B) 3.33 Ω
(C) 0.3 Ω
(D) None of the above
Answer:
(B) 3.33 Ω

Explanation:
$\frac{R_{1} R_{2}}{R_{1}+R_{2}}$ = $\frac{5 \times 10}{5+10}$
= 3.33 Ω

Question 5.

Equivalent resistance in series combination is:

(A) 15 Ω
(B) 3.33 Ω
(C) 0.3 Ω
(D) None of the above
Answer:
(A) 15 Ω

Explanation:
Series combination Rs = R₁ + R₂ = 5 + 10 = 15 Ω

VIII. Study the given circuit diagram and answer any of the four questions given below from Question 1. to Question 5.

Question 1.

Effective resistance of two 8 Ω resistors in the combination.

(A) 40
(B) 160
(C) 80
(D) lO
Answer:
(A) 40

Explanation:
$\vec{a}$ = $\vec{a}$ + $\vec{a}$ = $\vec{a}$
R = 4Ω

Question 2.

Current flowing through 4Ω resistor is :

(A) 1A
(B) 2A
(C) 8A
(D) 4A
Answer:
(A) 1A

Explanation:
Current flowing through the circuit = Current flowing through 4Ω Equivalent resistance of the circuit = 4Ω + 4Ω = 8Ω
Current flowing in the circuit = $\frac{V}{R}$ = $\frac{8 \mathrm{~V}}{8 \Omega}$ = 1A

Question 3.

Potential difference across 4Ω resistor is :

(A) 1V
(B) 2V
(C) 4V
(D) 8V
Answer:
(C) 4V
Explanation:
Potential difference across 4Ω = V₁
V₁ = IR₁
V₁ = 1A x 4Ω = 4V

Question 4.

Power dissipated in 4Ω resistor is : A

(A) 4W
(B) 2W
(C) 1W
(D) 8W
Answer:
(A) 4W

Explanation:
Power dissipated in 4Ω=p
p = VI = 4V x 1A = 4 watt

Question 5.

Difference in reading of ammeter A₁ and A₂

(A) will become double
(B) will become half
(C) remains the same
(D) 8A
Answer:
(C) remains the same

Explanation:
Since the resistance are in series combination, hence same current will flow through each resistor. Hence ammeter reading will be same.

MCQ Questions for Class 10 Science with Answers

MCQ Questions for Class 10 Science Chapter 12 Electricity Read More »

MCQ Questions for Class 10 Science Chapter 11 Human Eye and Colourful World

MCQ Questions / Prasanna

Human Eye and Colourful World Class 10 MCQ Questions With Answers

Question 1.

Study the following ray diagram :

In this diagram, the angle of incidence, the angle of emergence and the angle of deviation respectively have been represented by

(A) y, p and z
(B) x, q and z
(C) p, y and z
(D) p, z and y
Answer:
(C) p, y and z

Explanation:
Angle p is the angle of incidence as this angle is formed between the incident ray and the normal. Angle y is angle of emergence as it is formed between emergent ray and the normal, and angle z is the angle of deviation as it is formed between the emergent ray and the incident ray. Hence, the correct answer is p, y, z.

Question 2.

Which of the following phenomena of light are involved in the formation of a rainbow?

(A) Reflection, refraction and dispersion
(B) Refraction, dispersion and total internal reflection
(C) Refraction, dispersion and internal reflection
(D) Dispersion, scattering and total internal reflection
Answer:
(C) Refraction, dispersion and internal reflection

Explanation:
Dispersion means white light getting segregated into its component colours. Refraction bends the incident light to an angle that causes internal reflection and finally rainbow is formed.

Question 3.

Twinkling of stars is due to atmospheric

(A) dispersion of light by water droplets
(B) refraction of light by different layers of varying refractive indices
(C) scattering of light by dust particles
(D) internal reflection of light by clouds
Answer:
(B) refraction of light by different layers of varying refractive indices
Explanation:
Due to refraction of light by different layers of varying refractive indices, the apparent position of source of light keeps on changing. So stars appear to twinkle.

Question 4.

At noon the sun appears white as

(A) light is least scattered.
(B) all the colours of the white light are scattered awav.
(C) blue colour is scattered the most.
(D) red colour is scattered the most.
Answer:
(A) light is least scattered.

Explanation:
Sun is directly over the head and sunlight travel relatively shorter distance causing only little of the blue and violet colours to be scattered.

Question 5.

The clear sky appears blue because

(A) blue light gets absorbed in the atmosphere
(B) ultraviolet radiations are absorbed in the atmosphere
(C) violet and blue lights get scattered more than light of all other colours by the atmosphere
(D) light of all other colours is scattered more than the violet and blue colour light by the atmosphere
Answer:
(C) violet and blue lights get scattered more than light of all other colours by the atmosphere

Explanation:
A clear cloudless day-time sky is blue because molecules in the air scatter blue light from the sun more than they scatter red light. Rayleigh scattering is inversely proportional to the fourth power of wavelength, so that shorter wavelength violet and blue light will scatter more than the longer wavelengths (yellow and especially red light).

Question 6.

Which of the following statements is correct regarding the propagation of light of different colours of white light in air?

(A) Red light moves fastest
(B) Blue light moves faster than green light
(C) All the colours of the white light move with the same speed
(D) Yellow light moves with the mean speed as that of the red and the violet light
Answer:
(C) All the colours of the white light move with the same speed

Explanation:
Speed of light is a constant value regardless of its colour.

Question 7.

Which of the following phenomena contributes significantly to the reddish appearance of the sun at sunrise or sunset?

(A) Dispersion of light
(B) Scattering of light
(C) Total internal reflection of light
(D) Reflection of light from the earth
Answer:
(B) Scattering of light

Explanation:
Red colour scatters the least so that it travels the farthest. During sunset or sunrise, light has to travel a longer distance to reach us. Hence, only red light reaches to us and the sky appears reddish.

Question 8.

In an experiment to trace the path of a ray of light through a triangular glass prism, a student would observe that the emergent ray

(A) is parallel to the incident ray.
(B) is along the same direction of incident ray.
(C) gets deviated and bends towards the thinner part of the prism.
(D) gets deviated and bends towards the thicker part (base) of the prism.
Answer:
(D) gets deviated and bends towards the thicker part (base) of the prism.

Explanation:
As ray emerges out of the prism, it moves from a denser to a rarer medium, and therefore, bends away from the normal. So, bends towards the thicker part (base) of the prism.

Question 9.

Study the following figure in which a student has marked the angle of incidence (∠i), angle of refraction (∠r), angle of emergence (∠e), angle of prism (∠A) and the angle of deviation (∠D). The correctly marked angles are:

Answer:
(A) ∠A and ∠i
(B) ∠A, ∠i and ∠r
(C) ∠A, ∠i, ∠e and ∠d
(D) ∠A, ∠i, ∠r and ∠d
Explanation:
The correctly marked angles are of ∠A and ∠i.

Assertion and Reason Based MCQs

Question 1.

Assertion (A): A white light on passing through prism splits into its component colours as such that the red light emerges nearest to the base of the prism.
Reason (R): Wavelength of red light is more than other component colours and hence, red light deviates least.

Answer:
(D) A is false and R is true.

Explanation:
Dispersion takes place because the refractive index of medium for different wavelengths (colours) is different. The refractive index is inversely proportional to X Since kred is more than other colours wavelength. So, deviation is least for red and it appears farthest from the base of the prism.

Question 2.

Assertion (A): Sunlight reaches us without dispersion in the form of white light and not as its components.
Reason (R): Dispersion takes place due to variation of refractive index for different wavelength but in vacuum the speed of light is independent of wavelength and hence vacuum is a non-dispersive medium.

Answer:
(A) Both A and R are true and R is the correct explanation of A.

Explanation:
In vacuum speed of light is independent of wavelength. Hence, no dispersion takes places in vacuum. Thus, vacuum is a non-dispersive medium in which all colours travel with the same speed.

Question 3.

Assertion (A): In case of rainbow, light at the inner surface of the water drop gets internally reflected.
Reason (R): The angle between the refracted ray and normal to the drop surface is greater than the critical angle.

Answer:
(A) Both A and R are true and R is the correct explanation of A.

Explanation:
The rainbow is formed when light at the inner surface of the water drop gets internally reflected. If the angle between the refracted ray and normal to the drop surface is greater than the critical angle.

Question 4.

Assertion (A): Scattering of light is the reflection of light from an object in all directions.
Reason (R): The colour of scattered light depends on the size of scattering particles and wavelength of light.

Answer:
(B) Both A and R are true but R is NOT the correct explanation of A.

Explanation:
The reflection of light from an object in all direction is called scattering of light. The colour of scattered light depends on the size of scattering particles and wavelength of light. Very fine particles scatter mainly blue light while particles of larger size scatter light of longer wavelength i.e. red light. If the size of the scattering particles is large enough, then the scattered light may even appear white.

Case-Based MCQs

Attempt any 4 sub-parts from each question. Each sub-part carries 1 mark.
I. A narrow beam of white light is passing through a glass prism as shown in the diagram. Study the diagram and answer any four questions from Question 1. to Question 5.

Question 1.

The phenomenon observed in above set-up is

(A) scattering of light
(B) dispersion of light
(C) reflection of light
(D) refraction of light
Answer:
(B) dispersion of light

Explanation:
The phenomenon of splitting of white light into its constituent colours after passing through a prism is called as dispersion of light. When the light enters the prism, all the colours have different speeds due to which its gets split into bands.

Question 2.

In nature, this phenomenon is observed in

(A) Formation of rainbow
(B) Twinkling of stars
(C) Blue colour of sky
(D) Advance sunrise
Answer:
(A) Formation of rainbow

Explanation:
Rainbow is caused by dispersion of sunlight by tiny water droplets present in the atmosphere which is one of the application of dispersion of light.

Question 3.

Which of the following statement is correct about constituents of white light based on above observations?

(A) White light consists of seven colours.
(B) Violet colour suffers minimum deviation.
(C) Red light suffers maximum deviation.
(D) All the colours of the white light move with different speed in vacuum.
Answer:
(A) White light consists of seven colours.

Explanation:
When the light disperses, various bands of light are clearly visible. It is clear from the figure that the violet light suffers maximum deviation and red light suffers minimum deviation .All the colours of the white light move with the same speed in air or vacuum but with different wavelengths and frequencies.

Question 4.

The cause of dispersion of light is

(A) All the colors of light travel with the speed more than the speed of light.
(B) All the colors have different angles of deviation.
(C) All the colors do not travel with the same speed of light.
(D) All the colors have the same wavelength .
Answer:
(C) All the colors do not travel with the same speed of light.

Explanation:
The various colours of white light have different extent of refraction in a medium, All of colours of light do not travel with same speed in the medium which is the cause of dispersion of light.

Question 5.

Read the following statements carefully

(i) The prism behaves same as that of rectangular glass slab.
(ii) All the colours have different angles of deviation in case of dispersion through prism.
(iii) All the colours travel with the same speed of light in glass.
(iv) Dispersion of light is observed in case of rectangular glass slab.

Question 6.

Which of the above statements is true?

(A) Only (ii)
(B) (i) and (ii) only
(C) (i), (ii) and (iv) only
(D) All of the above
Answer:
(A) Only (ii)

Explanation:
A prism is made up of glass in which the faces are joined at a certain angle but in case of rectangular glass slab, the opposite faces are parallel to each other. As the light enters in the prism, all the colours travel with the different speed of light because glass is a denser medium as compared to air and dispersion of light is not observed in case of a rectangular glass slab. So, both prism and rectangular glass slab behave differently.

MCQ Questions for Class 10 Science with Answers

MCQ Questions for Class 10 Science Chapter 11 Human Eye and Colourful World Read More »

MCQ Questions for Class 10 Science Chapter 10 Light Reflection and Refraction

MCQ Questions / Prasanna

Light Reflection and Refraction Class 10 MCQ Questions With Answers

Question 1.

The laws of reflection hold true for:

(A) plane mirrors only
(B) concave mirrors only
(C) convex mirrors only
(D) all reflecting surfaces
Answer:
(D) all reflecting surfaces

Explanation:
The laws of reflection hold true for all reflecting surfaces.

$MCQ Questions for Class 10 Science Chapter 10 Light Reflection and Refraction$

Question 2.

When an object is kept within the focus of a concave mirror, an enlarged image is formed behind the mirror. This image is:

(A) real
(B) inverted
(C) virtual and inverted
(D) virtual and erect
Answer:
(D) virtual and erect

Explanation:
When an object is kept within the focus of a concave mirror, an enlarged image is formed behind the mirror. This image is virtual and erect.

Question 3.

Consider the following properties of virtual images:

(i) cannot be projected on the screen
(ii) are formed by both concave and convex lens
(iii) are always erect
(iv) are always inverted The correct properties are:

(A) (i) and (iv)
(B) (i) and (ii)
(C) (i), (ii) and (iii)
(D) (i), (ii) and (iv)
Answer:
(C) (i), (ii) and (iii)

Explanation:
A virtual image is formed when reflected rays appear to meet. Such images cannot be obtained on screen. Plane mirrors, convex mirror and concave lens always forms virtual image. They are always erect.

Question 4.

A real image is formed by the light rays after reflection or refraction when they:

(i) actually meet or intersect with each other.
(ii) actually converge at a point.
(iii)appear to meet when they are produced in the backward direction.
(iv) appear to diverge from a point.

Which of the above statements are correct?

(A) (i) and (iv)
(B) (ii) and (iv)
(C) (i) and (ii)
(D) (ii) and (iii)
Answer:
(C) (i) and (ii)

Explanation:
A real image is formed when light rays actually meet or intersect at a point after reflection or refraction.

Question 5.

The correct sequencing of angle of incidence, angle of emergence, angle of refraction and lateral displacement shown in the following diagram by digits 1,2, 3 and 4 is:

$MCQ Questions for Class 10 Science Chapter 10 Light Reflection and Refraction 1$
(A) 2,4,1, 3
(B) 2,1, 4, 3
(C) 1, 2, 4, 3
(D) 2,1, 3, 4
Answer:
(B) 2,1, 4, 3

Explanation:
Angle 2 is angle of incidence, as it is formed between the incident ray and the normal.Angle is angle of emergence, as it is formed between the emergent ray with normal. Angle 4 is angle of reflection as it is formed between the refracted ray and the normal. 3 shows the lateral displacement. Hence, the correct answer is 2,1,4,3.

$MCQ Questions for Class 10 Science Chapter 10 Light Reflection and Refraction$

Question 6.

A student obtained a sharp image of a candle flame placed at the distant end of the laboratory table on a screen using a concave mirror to determine its focal length. The teacher suggested him to focus a distant building about 1 km far from the laboratory, for getting more correct value of the focal length. In order to focus the distant building on the same screen the student should slightly move the:

(A) mirror away from the screen
(B) screen away from the mirror
(C) screen towards the mirror
(D) screen towards the building
Answer:
(C) screen towards the mirror

Explanation:
The object is at infinity , so to Obtain sharp image screen should be moved towards mirror.

Question 7.

Select from the following the best experimental set-up for tracing the path of a ray of light passing through a rectangular glass slab:

$MCQ Questions for Class 10 Science Chapter 10 Light Reflection and Refraction 2$

(A) P
(B) Q
(C) R
(D) S
Answer:
(D) S

Explanation:
Among the given options, S will the most suitable set up for tracing a ray of light passing through a rectangular glass slab.

Question 8.

To determine the approximate value of the focal length of a given concave mirror, you focus the image of a distant object formed by the mirror on a screen. The image obtained on the screen, as compared to the object is always:

(A) Laterally inverted and diminished
(B) Inverted and diminished
(C) Erect and diminished
(D) Erect and highly diminished
Answer:
(B) Inverted and diminished

Explanation:
When the object is at infinity, diminished, inverted and real image is formed.

Question 9.

In your laboratory you trace the path of light rays through a glass slab for different values of angle of incidence (∠i) and in each case measure the values of the corresponding angle of refraction (∠r) and angle of emergence (∠e).
On the basis of your observation your correct conclusion is:

(A) ∠i is more than ∠r, but nearly equal to ∠e
(B) ∠i is less than ∠r, but nearly equal to ∠e
(C) ∠i is more than ∠e, but nearly equal to ∠r
(D) ∠i is less than ∠e, but nearly equal to ∠r
Answer:
(A) ∠i is more than ∠r, but nearly equal to ∠e

Explanation:
When a ray of light passes through the glass slab, then the angle of incidence is found to be nearly equal to angle of emergence and greater than angle of refraction.

Question 10.

Which of the following can make a parallel beam of light when light from a point source is incident on it?

(A) Concave mirror as well as convex lens
(B) Convex mirror as well as concave lens
(C) Two plane mirrors placed at 90° to each other
(D) Concave mirror as well as concave lens
Answer:
(A) Concave mirror as well as convex lens

Explanation:
When a point source of light is placed at the focus of concave mirror then all light rays after reflection through mirror will become parallel to the principal axis.
When this point source of light is placed at the focus of convex lens then after refraction by light rays convex lens will become parallel to the principal axis.

$MCQ Questions for Class 10 Science Chapter 10 Light Reflection and Refraction$

Question 11.

Magnification produced by a rear-view mirror fitted in vehicles

(A) is less than one.
(B) is more than one.
(C) is equal to one.
(D) can be more than or less than one depending upon the position of the object in front of it.
Answer:
(A) is less than one.

Explanation:
Convex mirror is used as rear¬view mirror in vehicles. It forms virtual, erect, and diminished images of the objects. Magnification is ratio of height of image to the height of the object, hence, magnification produced by a rear-view mirror fitted in vehicles is less than one.

Question 12.

Rays from sun converge at a point 15 cm in front of a concave mirror. Where should an object be placed so that size of its image is equal to the size of the object?

(A) 15 cm in front of the mirror
(B) 30 cm in front of the mirror
(C) Between 15 cm and 30 cm in front of the mirror
(D) More than 30 cm in front of the mirror
Answer:
(B) 30 cm in front of the mirror

Explanation:
The distance of the sun is infinite as compared to the radius of curvature of concave mirror, so, light rays from sun incident parallel all the rays converge at the principal focus. So, the focal length is 15 cm. In case of a concave mirror, the size of image and object will be same if the object is placed at 2f. Hence, in this case object must be placed at 2/or 2×15 = 30 cm.

Question 13.

In torches, search lights and headlights of vehicles, the bulb is placed

(A) between the pole and the focus of the reflector.
(B) very near to the focus of the reflector.
(C) between the focus and centre of curvature of the reflector.
(D) at the centre of curvature of the reflector.
Answer:
(B) very near to the focus of the reflector.

Explanation:
The rays of light passing through the principal focus will go parallel to principal axis after reflection thus, forming a concentrated beam of light. So, due to this reason in torches, search lights, and headlights of vehicles, the bulb is placed very near to the focus of the reflector.

Question 14.

Which of the following ray diagrams is correct for the ray of light incident on a concave mirror as shown in figure?

$MCQ Questions for Class 10 Science Chapter 10 Light Reflection and Refraction 3$
$MCQ Questions for Class 10 Science Chapter 10 Light Reflection and Refraction 4$

(A) Fig. A
(B) Fig. B
(C) Fig. C
(D) Fig. D
Answer:
(D) Fig. D

Explanation:
In case of concave mirror, an incident ray parallel to principle axis passes through F after reflection.

Question 15.

A student determines the focal length of a device ‘X’ by focussing the image of a distant object on a screen placed 20 cm from the device on the same side as the object. The device ‘X’ is

(A) Concave lens of focal length 10 cm
(B) Convex lens of focal length 20 cm
(C) Concave mirror of focal length 10 cm
(D) Concave mirror of focal length 20 cm
Answer:
(D) Concave mirror of focal length 20 cm

Explanation:
Image formed by the concave mirror in this case is same as when object is at infinity. Due to the great distance, light rays will incident almost parallel to principal axis. After reflection all the rays will converge and meet at principal focus. So, focal length is 20 cm.

Question 16.

A student obtains a blurred image of a distant object on a screen using a convex lens. To obtain a distinct image on the screen he should move the lens

(A) away from the screen
(B) towards the screen
(C) to a position very far away from the screen
(D) either towards or away from the screen depending upon the position of the object
Answer:
(D) either towards or away from the screen depending upon the position of the object

Explanation:
The incident rays coming from the distant object will be parallel to the principal axis and as we know the rays parallel to the principal axis, after refraction by convex lens, will pass through the principal focus. Hence, a distinct image will be obtained immediately when distance between screen and lens is equal to focal length, so option (D) is correct choice.

$MCQ Questions for Class 10 Science Chapter 10 Light Reflection and Refraction$

Question 17.

A student very cautiously traces the path of a ray through a glass slab for different values of the angle of incidence (∠i). He then measures the corresponding values of the angle of refraction (∠r) and the angle of emergence (∠e) for every value of the angle of incidence. On analyzing these measurements of angles, his conclusion would be

(A) ∠i > ∠r > ∠e
(B) ∠i = ∠e > ∠r
(C) ∠i < ∠r < ∠e
(D) ∠i = ∠e < ∠r
Answer:
(B) ∠i = ∠e > ∠r

Explanation:
(Angle of incidence) ∠i = ∠e (angle of emergence) because the direction of incident ray and emergent ray is parallel to each other.
∠e >∠r (angle of refraction) because at point of emergence light is entering into optically rarer medium (air) from optically denser medium (glass), so light will bend away from the normal making the angle bigger.

Question 18.

An optical device has been given to a student and he determines its focal length by focusing the image of the sun on a screen placed 24 cm from the device on the same side as the sun. Select the correct statement about the device

(A) Convex mirror of focal length 12 cm
(B) Convex lens of focal length 24 cm
(C) Concave mirror of focal length 24 cm
(D) Convex lens of focal length 12 cm
Answer:
(C) Concave mirror of focal length 24 cm

Explanation:
Because the screen is on the same side of the object which means it cannot be a lens because it happens behind the lenses in such case. Moreover, concave mirror forms real images, that is, image can be obtained on a screen.

Question 19.

Study the given ray diagrams and select the correct statement from the following:

$MCQ Questions for Class 10 Science Chapter 10 Light Reflection and Refraction 5$
(A) Device X is a concave mirror and device Y is a convex lens, whose focal lengths are 20 cm and 25 cm respectively.
(B) Device X is a convex lens and device Y is a concave mirror, whose focal lengths are 20 cm and 25 cm respectively.
(C) Device X is a concave lens and device Y is a convex mirror, whose focal lengths are 20 cm and 25 cm respectively.
(D) Device X is a convex lens and device Y is a concave mirror, whose focal lengths are 20 cm and 25 cm respectively.
Answer:
(D) Device X is a convex lens and device Y is a concave mirror, whose focal lengths are 20 cm and 25 cm respectively.

Question 20.

A student obtains a blurred image of a distant object on a screen using a convex lens. To obtain a distinct image on the screen he should move the lens:

(A) away from the screen
(B) towards the screen
(C) to a position very far away from the screen
(D) either towards or away from the screen depending upon the position of the object.
Answer:
(D) either towards or away from the screen depending upon the position of the object.

Question 21.

A teacher sets up the stand carrying a convex lens of focal length 15 cm at 42.7 cm mark on the optical bench. He asks four students A, B, C and D to suggest the position of screen on the optical bench so that a distinct image of a distant tree is obtained almost immediately on it. The positions suggested by the students were as :

(i) 12.7 cm
(ii) 29.7 cm
(iii) 57.7 cm
(iv) 72.7 cm

The correct position of the screen was suggested by

(A) (i)
(B) (ii)
(C) (iii)
(D) (iv)
Answer:
(C) (iii)

Explanation:
The incident rays coming from the distant tree placed will be parallel to the principal axis and as we know the rays parallel to the principal axis, after refraction by convex lens, will pass through the principal focus. Hence, a distinct image will be obtained immediately when distance between screen and lens is equal to focal length. 42.7 cm (position of lens on optical bench) + 15 cm (focal length of lens) = 57.7 (the position of screen on optical bench)

Question 22.

To determine the approximate focal length of the given convex lens by focussing a distant object (say, a sign board), you try to focus the image of the object on a screen. The image you obtain on the screen is always

(A) erect and laterally inverted
(B) erect and diminished
(C) inverted and diminished
(D) virtual, inverted and diminished
Answer:
(C) inverted and diminished

Explanation:
The image formed by lens will be inverted and diminished.

$MCQ Questions for Class 10 Science Chapter 10 Light Reflection and Refraction$

Question 23.

Suppose you have focussed on a screen the image of candle flame placed at the farthest end of the laboratory table using a convex lens. If your teacher suggests you to focus the parallel rays of sun, reaching your laboratory table, on the same screen, what you are expected to do is to move the:

(A) lens slightly towards the screen
(B) lens slightly away from the screen
(C) lens slightly towards the sun
(D) lens and screen both towards the sun

Explanation:
The candle is at the farthest end of the laboratory. SO, it may be considered at a distance greater that 2Fj and hence the image of formed between F₂ and ZF₂. when the sun will be focussed, the image will be formed as F₂. SO, the lens is to the shifted towards the screen.

Question 24.

A spherical mirror and a thin spherical lens have each a focal length of -15 cm. The mirror and the lens are likely to be

(A) both concave.
(B) both convex.
(C) the mirror is concave and the lens is convex.
(D) the mirror is convex, but the lens is concave. R
Answer:
(A) both concave.

Explanation:
As per the sign convention, the focal length of a concave mirror and a concave lens are taken as negative. Hence, both the spherical mirror and the thin spherical lens are concave in nature.

Question 25.

Which of the following lenses would you prefer to use while reading small letters found in a dictionary?

(A) A convex lens of focal length 50 cm
(B) A concave lens of focal length 50 cm
(C) A convex lens of focal length 5 cm
(D) A concave lens of focal length 5 cm
Answer:
(C) A convex lens of focal length 5 cm

Explanation:
A magnified image of an object will be obtained when it is placed between the optical centre and focus of a convex lens. Magnification is also higher for convex lenses having shorter focal length. Therefore, for reading small letters, a convex lens of focal length 5 cm should be used.

Question 26.

Figure shows a ray of light as it travels from medium A to medium B. Refractive index of the medium B relative to medium A is

$MCQ Questions for Class 10 Science Chapter 10 Light Reflection and Refraction 6$
(A) $\frac{\sqrt{3}}{\sqrt{2}}$
(B) $\frac{\sqrt{2}}{\sqrt{2}}$
(C) $\frac{1}{\sqrt{2}}$
(D) $\sqrt{2}$
Answer:
(A) $\frac{\sqrt{3}}{\sqrt{2}}$

Explanation:
Here, angle of incidence = 60° Angle of refraction = r = 45° Refractive index of the medium B relative to medium A
=n_BA= $\frac{\sin i}{\sin r}$ = $\frac{\sin 60^{\circ}}{\sin 45^{\circ}}$
= $=\frac{\frac{\sqrt{3}}{2}}{\left(\frac{1}{\sqrt{2}}\right)}$= $\frac{\sqrt{3}}{\sqrt{2}}$

Question 27.

A light ray enters from medium A to medium B as shown in the figure. The refractive index of medium B relative to A will be

$MCQ Questions for Class 10 Science Chapter 10 Light Reflection and Refraction 7$

(A) Greater than unity
(B) Less than unity
(C) Equal to unity
(D) Zero
Answer:
(A) Greater than unity

Explanation:
Since, light rays in medium B go towards normal, so it has greater refractive index and lesser velocity of light with respect to medium A. So refractive index of medium B with respect to medium A is greater than unity.

Question 28.

Which of the following statements is true?

(A) A convex lens has 4 dioptre power having a focal length 0.25 m
(B) A convex lens has – 4 dioptre power having a focal length 0.25 m
(C) A concave lens has 4 dioptre power having a focal length 0.25 m
(D) A concave lens has – 4 dioptre power having a focal length 0.25 m
Answer:
(A) A convex lens has 4 dioptre power having a focal length 0.25 m

Explanation:
The power (P) of a lens of focal length (f) is given by P = 1/f where f is the focal length meter and power in dioptre.
Now, p = 1/f

or $4=\frac{1}{f}$
or $f=\frac{1}{4} \mathrm{~m}$=0.25m

Assertion and Reason Based Mcqs

Question 1.

Assertion (A): Plane mirror may form real image.
Reason (R): Plane mirror forms virtual image, if object is real.

Answer:
(B) Both A and R are true but R is NOT the correct explanation of A.

Explanation:
Plane mirror may form real image, if object is virtual.
$MCQ Questions for Class 10 Science Chapter 10 Light Reflection and Refraction 8$

Question 2.

Assertion (A): The focal length of the convex mirror will increase, if the mirror is placed in water.
Reason (R): The focal length of a convex mirror of radius R is equal to, f = $\frac{R}{2}$

Answer:
(D) A is false and R is True

Explanation:
Focal length of the spherical mirror does not depend on the medium in which it is placed.

$MCQ Questions for Class 10 Science Chapter 10 Light Reflection and Refraction$

Question 3.

Assertion (A): The image formed by a concave mirror is certainly real if the object is virtual.
Reason (R): The image formed by a concave mirror is certainly virtual if the object is real.

Answer:
(C) A is true but R is false.

Explanation:
The image of real object may be real in case of concave mirror.

Question 4.

Assertion (A): An object is placed at a distance of from a convex mirror of focal length its image will form at infinity.
Reason (R): The distance of image in convex mirror can never be infinity.

Answer:
(D) A is false and R is True

Explanation:
The distance of image in convex I mirror is always finite.

Question 5.

Assertion (A): If the rays are diverging after emerging from a lens; the lens must be concave.
Reason (R): The convex lens can give diverging rays.

Answer:
(D) A is false and R is True

Explanation:
If the rays cross focal point of convex lens, they become diverging.

Question 6.

Assertion (A): Refractive index of glass with respect to air is different for red light and violet light.
Reason (R): Refractive index of a pair of media depends on the wavelength of light used.

Answer:
(A) Both A and R are true and R is the correct explanation of A.

Explanation:
Refractive index of any pair of media is inversely proportional to wavelength of light.
Hence, λ_v < λ_r
so, µ_r < µ_v
where, λ_v and < λ_r are the wavelengths of violet and red light.µ_r and < µ_v are refractive index of violet and red light.

$MCQ Questions for Class 10 Science Chapter 10 Light Reflection and Refraction$

Question 7.

Assertion (A): The refractive index of diamond is √6 and refractive index of a liquid is S. If the light travels from diamond to the liquid, it will be initially reflected when the angle of incidence is 30°. 1
Reason (R):$\mu=\frac{1}{\sin C}, $
where µ is the refractive index of diamond with respect to liquid.

Answer:
(A) Both A and R are true and R is the correct explanation of A.

Explanation:
Refractive index of diamond w.r.t. liquid
${ }^{d} \mu_{l}=\frac{1}{\sin C}=\frac{\mu_{d}}{\mu_{l}} \Rightarrow \frac{\sqrt{6}}{\sqrt{3}}=\frac{1}{\sin C}$
sin C = $\frac{1}{\sqrt{2}}$ sin 45°
∴C = 45°

Question 8.

Assertion: Light travels faster in glass than in air.
Reason: Glass is denser than air.

Answer:
(D) A is false and R is True

Explanation:
Light travels faster in air than in glass, because glass is denser than air.

Case-Based MCQs

Attempt any 4 sub-parts from each question. Each sub-part carries 1 mark.
I. Following figure illustrates the ray diagram for the formation of image by a concave mirror. The position of the object is beyond the centre of curvature of the concave mirror. On the basis of given diagram answer any four questions from
$MCQ Questions for Class 10 Science Chapter 10 Light Reflection and Refraction 9$
Question 1.

If the focal length of the concave mirror is 10 cm, the image formed will be at a distance .

(A) Between 10cm and 15cm
(B) Between 10cm and 20cm
(C) Beyond 20cm
(D) At 20 cm
Answer:
(B) Between 10cm and 20cm

Explanation:
If the focal length of the concave mirror is 10 cm, the image formed will be at a distance between 10 cm and 15 cm.

Question 2.

In case of concave mirror, the image distance is………. when image is formed in front of the mirror and………..when the image is formed behind the mirror.

(A) positive, negative
(B) negative, negative
(C) negative, positive
(D) positive, positive
Answer:
(C) negative, positive

Explanation:
If an image formed behind the concave mirror, the object distance is positive but if an image is formed in front of the mirror, the image distance is negative.

Question 3.

If the size of the object in the given figure is 5 cm and the magnification produced is -0.5. The size of the image is (in cm)…………..

(A) -2.5
(B) -0.1
(C) 2.5
(D) 0.1
Answer:
(A) -2.5

Explanation:
As we know, magnification,
m=$\frac{h_{2}}{h_{1}} $
h₂ = $\frac{-(0.5 \times 5)}{10}$
h₂ = -2.5

$MCQ Questions for Class 10 Science Chapter 10 Light Reflection and Refraction$

Question 4.

A negative sign in the magnification value indicate that the image is……….

(A) Real and inverted
(B) Real and erect
(C) Virtual and erect
(D) Virtual and inverted
Answer:
(A) Real and inverted

Explanation:
A negative sign in the magnification value indicate that the image is real and inverted.

Question 5.

An image formed by concave mirror is virtual, when the object is placed:

(A) at infinity
(B) at C
(C) Between C and F
(D) Between P and F
Answer:
(D) Between P and F

Explanation:
An image formed by concave mirror is virtual, when the object is placed between P and F.

II. Read the following passage and answer any four questions from Question 1. to Question 5.
A student wants to project the image of a candle flame on the walls of the school laboratory by using a mirror.

Question 1.

Which type of mirror should he use and why ?

(A) Convex mirror, it forms virtual image
(B) Concave mirror, it forms virtual image
(C) Concave mirror, it forms real image
(D) Convex mirror, it forms real image
Answer:
(C) Concave mirror, it forms real image

Explanation:
He should use a concave mirror as it forms real images.

Question 2.

At what distance, in terms of focal length of the mirror, should he place the candle flame to get the magnified image on the wall ? Q;

(A) At F
(B) Between F and C
(C) At C
(D) At infinity
Answer:
(B) Between F and C

Explanation:
He should place the candle flame between the focus and centre of curvature of the mirror to get the magnified image on the wall.

Question 3.

To get the diminished image of the candle flame, the object must be placed at:

(A) infinity
(B) at C
(C) between F and C
(D) At F
Answer:
(A) infinity

Explanation:
To get the diminished image of the candle flame, the object must be placed at infinity.

$MCQ Questions for Class 10 Science Chapter 10 Light Reflection and Refraction$

Question 4.

If the image formed by this mirror is inverted and real, the magnification will be: A

(A) Positive
(B) Negative
(C) Either of them
(D) None of the above
Answer:
(B) Negative

Explanation:
If the image formed by this mirror is inverted and real, the magnification will be negative.

Question 5.

A virtual image formed by concave mirror is:

(A) erect and enlarged
(B) erect and diminished
(C) inverted and diminished
(D) inverted and enlarged
Answer:
(A) erect and enlarged

Explanation:
A virtual image formed by concave mirror is erect and enlarged.

III. Read the following passage and answer any four questions from Question 1. to Question 5.
A student wants to project the image of a candle flame on a screen 60 cm in front of a mirror by keeping the flame at a distance of 15 cm from its pole.

Question 1.

Suggest the type of mirror he should use:

(A) convex mirror
(B) plane mirror
(C) concave mirror
(D) none of the above
Answer:
(C) concave mirror

Explanation:
He should use a concave mirror, as it forms a real image on the same side of the mirror.

Question 2.

Find the linear magnification of the image produced.

(A) – 4
(B) + 4
(C) – 900
(D) + 900
Answer:
(A) – 4

Explanation:
Object distance, u = -15 cm
Image distance, v = – 60 cm
Magnification, m = $\frac{-v}{u}=\frac{-(-60)}{(-15)}=-4 $

The minus sign in magnification shows that the image formed is real and inverted.

$MCQ Questions for Class 10 Science Chapter 10 Light Reflection and Refraction$

Question 3.

When object distance is less than focal length the image is and when object distance is more than focal length the image is .

(A) real in both case
(B) virtual in both case
(C) real, virtual
(D) virtual, real
Answer:
(D) virtual, real

Explanation:
When object distance is less than focal length the image is virtual and when object distance is more than focal length the image is real.

Question 4.

What is the distance between the object and its image ?

(A) 45 cm
(B) 35 cm
(C) 75 cm
(D) 0 cm
Answer:
(A) 45 cm

Explanation:
The image is formed at a distance of 45 cm from the object.

Question 5.

The image formed in the above case is:

(A) virtual, inverted and magnified.
(B) real, erect and magnified
(C) real, inverted and magnified
(D) real, erect and diminished
Answer:
(C) real, inverted and magnified

Explanation:
In this case, the image is formed beyond the centre of curvature. This image is real, inverted and enlarged.

IV Read the following passage and answer the following questions from Question 1. to Question 4.
A student focuses the image of a candle flame, placed at about 2 m from a convex lens of focal length 10 cm, on a screen. After that he moves gradually the flame towards the lens and each time focuses its image on the screen.

Question 1.

In which direction does he move the lens to focus the flame on the screen ?

(A) away from screen
(B) towards the screen
(C) should not move the screen
(D) toward the candle
Answer:
(D) toward the candle

Explanation:
Let us assume the screen to lens distance is greater than 20 cm. Since it is required to get image beyond 2F, the object should be F and 2F on other side of the lens. Hence student will move the lens towards candle. (F means a location at a distance from lens that equals the focal length of lens. 2F means distance that equals twice the focal length).

Question 2.

What happens to the size of the image of the flame formed on the screen?

(A) size of image will decrease
(B) size of image will increase
(C) remains unchanged
(D) size will become too small
Answer:
(B) size of image will increase

Explanation:
Size of the image of the flame increases when object is moving towards lens, from a distance beyond 2F, then 2F, then less than 2F.

$MCQ Questions for Class 10 Science Chapter 10 Light Reflection and Refraction$

Question 3.

What difference is seen in the intensity (brightness) of the image of the flame on the screen ?

(A) intensity of image increases
(B) intensity of image remains same
(C) intensity of image reduces
(D) the image disappears
Answer:
(A) intensity of image increases

Explanation:
As the object (candle) is moved towards lens more light intensity is collected by lens, hence brightness of the image increase.

Question 4.

What is seen on the screen when the flame is very close (at about 5 cm) to the lens ?

(A) a bright image
(B) a magnified image
(C) diminished image
(D) no image
Answer:
(D) no image

Explanation:
When the candle is very close about 5 cm, focussing the flame is not possible. Hence student will not get any image on the screen.
He will get diffused light on the screen.

V. Read the passage and note the following observations. Answer any four questions from Question 1. to Question 5.
A student focussed the image of a candle flame on a white screen by placing the flame at various distances from a convex lens. He noted his

Distance of flame from the lens (cm)	Distance of the screen from the lens (cm)
(A) 60	20
(B) 40	24
(C) 30	30
(D) 24	40
(E) 15	70

Question 1.

From the above table, find the focal length of lens without using lens formula: |AEI

(A) 15cm
(B) 30cm
(C) 40cm
(D) 60cm
Answer:
(A) 15cm

Explanation:
u = 30 cm, v = 30 cm This is possible if the object is placed at 2f ∴ 2f = 30 cm, f= 15 cm

Question 2.

Which set of observations is incorrect?

(A) (a)
(B) (c)
(C) (e)
(D) (d)
Answer:
(C) (e)

Explanation:
u = 15 cm, v = 70 cm is incorrect. This is because if the object is at focus then image is formed at infinity.

$MCQ Questions for Class 10 Science Chapter 10 Light Reflection and Refraction$

Question 3.

In which case, the size of the object and image will be same:

(A) In (D) case
(B) In (B) case
(C) In (C) case
(D) In (A) case
Answer:
(C) In (C) case

Explanation:
In (C) case, because object is at the centre of curvature.

Question 4.

What is the change in image observed as the object is moved from infinity towards the concave lens?

(A) Size of image decreases
(B) Size of image becomes highly diminished
(C) Size of the image remains unchanged
(D) Size of the image increases slightly
Answer:
(D) Size of the image increases slightly

Explanation:
The size of the image increases slightly, though it remains diminished in comparison to the size of the object.

Question 5.

Which of the following statement is false for the formation of images by convex lens?

(A) It forms real,inverted and diminished image.
(B) It forms virtual erect and enlarged image.
(C) It forms virtual, erect, and diminished image.
(D) It forms real,inverted and enlarged image.
Answer:
(C) It forms virtual, erect, and diminished image.

Explanation:
Image formed by a convex mirror is always diminished and erect.

VI. Study the given diagram and answer any four questions from Question 1. to Question 5.
A very thin narrow beam of white light is made incident on three glass objects shown below.
Study the nature and behaviour of the emergent beam in all the three cases.
$MCQ Questions for Class 10 Science Chapter 10 Light Reflection and Refraction 10$

Question 1.

Following are the possibility of two emergent beams being similar. Choose the correct answer:

(A) (i) and (ii)
(B) (i) and (iii)
(C) (ii) and (iii)
(D) No similar emergent beams
Answer:
(B) (i) and (iii)
Explanation:
In (i) emergent beam is white and laterally displaced. In (ii) emergent beam is a spectrum of seven colours bent in different angles. In (iii) emergent beam from the second prism is white only. Similarity between (i) and (iii) as both emergent rays are white in colour

$MCQ Questions for Class 10 Science Chapter 10 Light Reflection and Refraction$

Question 2.

When light enters from air to glass, the angles of incidence and refraction in air and glass are 45° and 30°, respectively. Find the refractive index of glass.

$\text { (Given that } \sin 45^{\circ}=\frac{1}{\sqrt{2}} ; \sin 30^{\circ}=\frac{1}{2} \text { ) } $
(A) √2
(B) 2√2
(C) 1/(√2)
(D) 1
Answer:
(A) √2

Explanation:
$a_{g}=\frac{\sin i}{\sin r}=\frac{\sin 45^{\circ}}{\sin 30^{\circ}} $
$=\frac{\frac{1}{\sqrt{2}}}{\frac{1}{2}}=\sqrt{2} $

Question 3.

The light changes its path as its medium changes. Which of the following is an incorrect statement ?

(A) Speed of light is different in different media.
(B) Light changes its path because light only travels in straight line.
(C) Speed of light is dependent on medium through which it is passing.
(D) The light chooses the path with minimum time, as it changes its medium.
Answer:
(B) Light changes its path because light only travels in straight line.

Explanation:
Speed of light is different in different media. As the medium changes, the light has to choose a path of minimum time. Hence, the direction of the light changes. This phenomenon is known as refraction of light.

Question 4.

What is the unit of refractive index? R

(A) Pascal
(B) Joule
(C) No unit
(D) p m
Answer:
(C) No unit

Explanation:
Refractive index being a ratio of two similar quantities hence has no unit.

$MCQ Questions for Class 10 Science Chapter 10 Light Reflection and Refraction$

Question 5.

Light travel fastest in:

(A) Air
(B) Vacuum
(C) Glass
(D) diamond
Answer:
(B) Vacuum

Explanation:
Light waves travel fastest through a vacuum and air, and slower through other materials such as glass or water.

MCQ Questions for Class 10 Science with Answers

MCQ Questions for Class 10 Science Chapter 10 Light Reflection and Refraction Read More »

MCQ Questions for Class 10 Science Chapter 9 Heredity and Evolution

MCQ Questions / Prasanna

Heredity and Evolution Class 10 MCQ Questions With Answers

Question 1.

Which of the following statement is incorrect?

(A) For every hormone there is a gene.
(B) For every protein there is a gene.
(C) For production of every enzyme there is a gene.
(D) For every molecule of fat there is a gene.
Answer:
(D) For every molecule of fat there is a gene.

Explanation:
Hormone and enzymes are proteins and formation of any particular protein is controlled by a particular gene. Hence, all other options are correct.

Question 2.

If a round, green seeded pea plant (RRyy) is crossed with wrinkled, yellow seeded pea plant, (rrYY) the seeds produced in F, generation are

(A) round and yellow.
(B) round and green.
(C) wrinkled and green.
(D) wrinkled and yellow.
Answer:
(A) round and yellow.

Explanation:
As roundness and yellow colour are shown by capital letters in the genotype, so they are dominant traits. In FI generation, only dominant traits are expressed.

Question 3.

The maleness of a child is determined by

(A)the X chromosome in the zygote.
(B) the Y chromosome in zygote.
(C) the cytoplasm of germ cell which determines the sex.
(D) sex is determined by chance.
Answer:
(B) the Y chromosome in zygote.

Explanation:
Y-chromosome in zygote means that the zygote would develop into a male I j child.

Question 4.

A zygote which has an X-chromosome inherited from the father will develop into a

(A) boy.
(B) girl.
(C) X- chromosome does not determine the sex of a child.
(D) either boy or girl.
Answer:
(B) girl.

Explanation:
A zygote with XX chromosomes in the 23rd pair would develop into a girl child.

Question 5.

From the list given below, select the character which can be acquired but not inherited.

(A) colour of eye.
(B) colour of skin.
(C) size of body.
(D) nature of hair.
Answer:
(C) size of body.

Explanation:
Traits in other options are always inheritable traits.

Question 6.

Two pink coloured flowers on crossing resulted in 1 red, 2 pink and 1 white flower progeny. The nature of the cross will be

(A) double fertilisation.
(B) self-pollination.
(C) cross fertilisation.
(D) no fertilization.
Answer:
(C) cross fertilisation.

Explanation:
As it is mentioned in the question that two pink coloured flowers were crossed, thus it is cross fertilization.

Question 7.

A cross between a tall plant (TT) and short pea plant (tt) resulted in progeny that were all tall plants because

(A) tallness is the dominant trait.
(B) shortness is the dominant trait.
(C) tallness is the recessive trait.
(D) height of pea plant is not governed by gene’T’ oi’t’.
Answer:
(A) tallness is the dominant trait.

Explanation:
This is a case of monohybrid cross, in which all the progenies in the FI generation show dominant character. Hence, tallness is the dominant trait.

Question 8.

The number of pair (s) of sex chromosomes in the zygote of humans is

(A) one.
(B) two.
(C) three.
(D) four.
Answer:
(A) one.

Explanation:
The sex chromosomes are in the 23rd pair.

Question 9.

In evolutionary terms, we have more in common with

(A) a Chinese school-boy.
(B) a chimpanzee.
(C) a spider.
(D) a bacterium.
Answer:
(A) a Chinese school-boy.

Explanation:
In evolutionary terms, we have more in common with a Chinese school boy as both are humans and belong to same species.

Question 10.

The theory of evolution of species by natural selection was given by

(A) Mendel
(B) Darwin
(C) Morgan
(D) Lamarck
Answer:
(B) Darwin

Explanation:
The theory of evolution of species by natural selection was given by Charles Darwin.

Question 11.

The theory of inheritance of acquired characters was given by

(A) Mendel
(B) Darwin
(C) Morgan
(D) Lamarck
Answer:
(D) Lamarck

Explanation:
The theory of inheritance of acquired characters was given by Lamarck.

Question 12.

If the fossil of an organism is found in the deeper layers of earth, then we can predict that

(A) the extinction of organism has occurred recently.
(B) the extinction of organism has occurred thousands of years ago.
(C) the fossil position in the layers of earth is not related to its time of extinction.
(D) time of extinction cannot be determined.
Answer:
(B) the extinction of organism has occurred thousands of years ago.

Explanation:
Newer fossils are deposited in layers above older fossils.

Assertion and Reason Based MCQs

Question 1.

Assertion: A geneticist crossed a pea plant having violet flowers with a pea plant having white flowers, he got all violet flowers in first generation. Reason: White colour gene is not passed on to next generation.

Answer:
(C) A is true but R is false.

Explanation: The gene for violet flowers is dominant over the gene for white flowers so that only the violet gene is expressed as violet flowers in the first generation.

Question 2.

Assertion (A): Mendel chose a number of varieties of garden pea as plant material for his experiments.
Reason (R): Garden pea has well defined characters and is bisexual.

Answer:
(A) Both A and R are true and R is the correct explanation of A.

Explanation:
Mendel chose garden pea as plant material for his experiment because garden pea plants were easily available they grow in one season fertilization was easy.

Question 3.

Assertion (A): In humans, males play an important role in determining the sex of the child.
Reason (R): Males have two X chromosomes.

Answer:
(C) A is true but R is false.

Explanation:
Sex of a child is dependent on the type of the male gamete that fuses with the female gamete. Human beings possess 23 pairs of chromosomes. Out of these, 22 pairs are known as autosomes, while the remaining one pair comprises sex chromosomes (XX in females and XY in males). At the time of fertilisation, the egg cell fuses with the sperm cell, resulting in the formation of the zygote. If the egg cell carrying an X chromosome fuses with the sperm carrying an X chromosome, the resulting child would be a girl. If the egg cell carrying an X chromosome fuses with the sperm carrying a Y chromosome, the resulting child would be a boy.

Question 4.

Assertion (A): Learning a skill such as dance and music is an acquired trait.
Reason (R): Acquired traits develop in the life time of an individual and do not pass to the progeny.

Answer:
(A) Both A and R are true and R is the correct explanation of A.

Explanation:
Trails which develop in the life time of an individual and do not pass to the progeny are called acquired traits. Learning a skill such as dance/music/loss of body parts/’ weight etc are example of acquired traits.

Question 5.

Assertion (A): Traits like eye colour or height are inherited traits.
Reason (R): Inherited traits are not transferred from parents to young ones.

Answer:
(C) A is true but R is false.

Explanation:
Eye colour and height are genetically inherited traits, as these are expressed by genes. Inherited traits are the traits which are transferred from parents to young ones. Acquired traits are the characters that are acquired by the individual during its lifetime. These traits cannot be inherited. For example, if a wrestler develops large muscles due to his training program that does not mean it will be passed on to his offspring.

Question 6.

Assertion (A): Fossils are remains of dead organisms.
Reason (R): It is helpful in study of evolution.

Answer:
(B) Both A and R are true but R is NOT the correct explanation of A.

Explanation:
Fossils are remains of hard parts of the dead organisms in the strata of earth. It help in tracing evolutionary pathways.

Question 7.

Assertion (A): Wings of butterfly and wings of bat are analogous orgAnswer:
Reason (R): Analogous organs have different origin and structural plan but same function.

Answer:
(A) Both A and R are true and R is the correct explanation of A.

Explanation:
Wings of butterfly and wings of bat though they perform similar function, they have different origin/basic structure. Hence, they are known as analogous orgAnswer:

Question 8.

Assertion (A): Speciation is the process of formation of a new species from a pre-existing one.
Reason (R): Mutation plays a role in speciation.

Answer:
Option (A) is correct.

Explanation:
Speciation is an evolutionary process by which new species arise. One of the factors that lead to speciation is mutation.

Question 9.

Assertion (A): Natural selection is the phenomenon by which the nature selects those species which possess survival advantage over the other species.
Reason (R): According to theory of natural selection, there is struggle of existence within the species of a population for the environmental resources and their struggle leads to survival of certain organisms and elimination of the less competent species.

Answer:
(A) Both A and R are true and R is the correct explanation of A.

Explanation:
Natural selection is the phenomenon by which the nature selects those species which possess survival advantage over the other species. According to theory of natural selection, there is struggle of existence within the species of a population for the environmental resources and their struggle leads to survival of certain organisms and elimination of the less competent species.

Case-Based MCQs

Attempt any 4 sub-parts from each question. Each sub-part carries 1 mark.

I. Read the passage and answer the following questions from Question 1. to Question 5.
In a cross between plants with purple flowers and plants with white flowers, the offspring of Fj generation all had white flowers. When the Fj generation was self-crossed, it was observed in the F2 generation that out of 100, 75 flowers were white. Make a cross and answer the following questions:

Question 1.

The above cross is known as:

(A) Monohybrid cross
(B) Dihybrid cross
(C) Test cross
(D) Back cross
Answer:
(A) Monohybrid cross

Explanation:
A cross between two plants, which differ in only one pair of contrasting characters is calld monohybrid cross. In this cross, F2 phenotypic ratio is 3 :1 and genotypic ratio is 1: 2 :1.

Question 2.

In a monohybrid cross between two heterozygous individuals, percentage of pure homozygous individuals obtained in F₁ generation is ?

(A) 25%
(B) 50%
(C) 75%
(D) 100%
Answer:
(B) 50%

Explanation:
In a monohybrid cross between two heterozygous individuals, percentage of pure homozygous individuals obtained in F, generation is 50 %.

Question 3.

Which of these is not the genotype of F progeny?

(A) WW
(B) Ww
(C) ww
(D) Wp
Answer:
(D) Wp

Explanation:
Genotypes of F₂ progeny are WW, Ww, ww.

Question 4.

The ratio of ‘White: Purple’ flowers in the F₂ generation is

(A) 3:1
(B) 1: 2
(C) 1 : 3
(D) 2 :1
Answer:
(A) 3:1

Explanation:
Ratio between White : Purple flowers are 3:1.

II. Study the given cross showing self pollination in F₁ and answer the following questions from Question 1. to Question 4.

Question 1.

The missing blank in the above cross is:

(A) RrYy
(B) RRYY
(C) RryY
(D) rryy
Answer:
(A) RrYy

Explanation:
RrYy (Round Yellow) is the I missing blank in the above cross.

Question 2.

The combination of characters in the F₂ progeny are:

(A) Round Yellow: Round Green: Wrinkled Yellow: Wrinkled Green
(B) Round Green : Round Yellow : Wrinkled yellow : Wrinkled Green
(C) Round Yellow : Round Green : Wrinkled Green: Wrinkled yellow
(D) Round Green : Round Yellow : Wrinkled yellow : Wrinkled Green
Answer:
(A) Round Yellow: Round Green: Wrinkled Yellow: Wrinkled Green

Explanation:
In F₂ generation, the combination of characters is Round Yellow: Round Green: Wrinkled yellow: Wrinkled Green.

Question 3.

The ratio of the combination of characters in the F₂ progeny is:

(A) 3: 1
(B) 1: 2: 1
(C) 1 1: 1
(D) 9 : 3 : 3 :1
Answer:
(D) 9 : 3 : 3 :1

Explanation:
The ratio of the combination of 8 characters in the F₂ progeny is 9: 3: 3:1.

Question 4.

A Mendelian experiment consists of breeding tall pea plants bearing violet flowers with short pea plants bearing white flowers. The progeny all bore violet flowers, but almost half of them were short. This suggests that the genetic make-up of the tall parent cod depicted as

(A) TTWW
(B) TTww
(C) TtWW
(D) TtWw
Answer:
(C) TtWW

Explanation:
All progeny bore violet flower, so they all must have gene for violet flower. As violet colour appears in hybrids thus it must be the dominant character. So, white flowered plant should have ww genes to show recessive white character. It indicates that all progenies got allele W (violet colour) from tall-violet flowered plant, thus its all gametes should have this allele. To serve the purpose plant must have WW genes. But, tallness was found in 50% progenies thus half of its gametes contained T gene and other half contained t gene. Inclusively, the tall plant had TtWW genotype.

III. Read the given passage and answer any of the four questions from Question 1. to Question 5. given below:
Seema crossed pure breed pea plants having round-yellow seeds with wrinkled green seeds and found that only A-B type of seeds were produced in the F, generation. When F, generation pea plants having A-B type of seeds were cross-breed by self pollination, then in addition to the original round yellow and wrinkled green seeds, two new varieties A-D and C-B types of seeds were also obtained.

Question 1.

What are A-B type of seeds?

(A) Round -yellow
(B) Round- green
(C) Wrinkled-yellow
(D) Wrinkled-green
Answer:
(A) Round -yellow

Explanation:
A-B type of seeds are round in shape and yellow in colour.

Question 2.

A and B are……… traits.

(A) dominant
(B) recessive
Answer:
(A) dominant

Explanation:
A-B type is dominant traits.

Question 3.

A-D are……… and C-B are ……….. type of seeds.

(A) Round green and wrinkled yellow respectively
(B) Round yellow and wrinkled green respectively
(C) Wrinkled green and round green respectively
(D) Wrinkled green and round yellow respectively
Answer:
(A) Round green and wrinkled yellow respectively

Explanation:
A-D is round-green while C-B is wrinkled- yellow.

Question 4.

Which one of these will be produced in minimum and maximum number in the F₂ generation?

(A) A-B
(B) A-D
Answer:
(A) A-B

Explanation:
A-B is produced in maximum number while A-D will be produced in minimum number.

Question 5.

The above cross is known as

(A) Monohybrid cross
(B) Dihybrid cross
(C) Test cross
(D) Back cross
Answer:
(B) Dihybrid cross

Explanation:
A cross between two plants, which differ in two pairs of contrasting characters are called dihybrid cross.

MCQ Questions for Class 10 Science with Answers

MCQ Questions for Class 10 Science Chapter 9 Heredity and Evolution Read More »

MCQ Questions for Class 10 Science Chapter 8 How do Organisms Reproduce?

MCQ Questions / Prasanna

How do Organisms Reproduce? Class 10 MCQ Questions With Answers

Question 1.

Reproduction is essential for living organisms in order to

(A) keep the individual organism alive.
(B) fulfill their energy requirement.
(C) maintain growth.
(D) continue the species generation after generation.
Answer:
(D) continue the species generation after generation.

Explanation:
Reproduction serves to continue the species which would otherwise extinct due to struggle for survival and natural/accidental death of individuals.

Question 2.

A feature of reproduction that is common to Amoeba, Spirogyra and Yeast are that

(A) they reproduce asexually.
(B) they are all unicellular.
(C) they reproduce only sexually.
(D) they are all multicellular.
Answer:
(A) they reproduce asexually.

Explanation:
All of them reproduce asexually. with single parent and no need of fusion of gametes.

Question 3.

In Spirogyra, asexual reproduction takes place by

(A) breaking up of filaments into smaller bits.
(B) division of a cell into two cells.
(C) division of a cell into many cells.
(D) formation of young cells from older cells.
Answer:
(A) breaking up of filaments into smaller bits.

Explanation:
Fragmentation is a type of asexual reproduction in animals in which parental body is broken down into pieces and each of these pieces develop into an individual animal.

Question 4.

The ability of a cell to divide into several cells during reproduction in Plasmodium is called

(A) budding
(B) reduction division
(C) binary fission
(D) multiple fission EES
Answer:
(D) multiple fission EES

Explanation:
Multiple fission is a repeated division of organism to produce many daughter cells all together.

Question 5.

Factors responsible for the rapid spread of bread mould on slices of bread are

(i) large number of spores.
(ii) availability of moisture and nutrients in bread,
(iii) presence of tubular branched hyphae.
(iv) formation of round shaped sporangia.

(A) (i) and (iii)
(B) (ii) and iv)
(C) (i) and (ii)
(D) (iii) and (iv)
Answer:
(C) (i) and (ii)

Explanation:
Bread mould prefers damp and warm substratum with ample supply of nutrients on which its air-borne spores land and germinate to produce mycelium.

Question 6.

In the list of organisms given below, those that reproduce by the asexual method are

(i) Banana
(ii) Dog
(iii) Yeast
(iv) Amoeba

(A) (ii) and (iv)
(B) (i), (iii) and (iv)
(C) (i) and (iv)
(D) (ii), (iii) and (iv)
Answer:
(B) (i), (iii) and (iv)

Question 7.

Offspring formed by asexual method of reproduction have greater similarity among themselves because

(i) asexual reproduction involves only one parent.
(ii) asexual reproduction does not involve gametes.
(iii) asexual reproduction occurs before sexual reproduction.
(iv) asexual reproduction occurs after sexual reproduction.

(A) (i) and (ii)
(B) (i) and (iii)
(C) (ii) and (iv)
(D) (iii) and (iv)
Answer:
(A) (i) and (ii)

Explanation:
Asexual reproduction does not 1 involve gamete formation and fertilization.

Question 8.

Vegetative propagation refers to formation of new plants from

(A) stem, roots and flowers.
(B) stem, roots and leaves.
(C) stem, flowers and fruits.
(D) stem, leaves and flowers.
Answer:
(B) stem, roots and leaves.

Explanation:
Flowers are the organs of sexual reproduction in plants.

Question 9.

Asexual reproduction takes place through budding in

(A) Amoeba
(B) Yeast
(C) Plasmodium
(D) Leishmania
Answer:
(B) Yeast

Explanation:
Asexual reproduction takes place through budding in yeast.

Question 10.

Which of the following are examples of vegetative reproduction in plants?

(A) Tomato, lady’s finger, onion and cauliflower
(B) Potato, ginger, onion and sugarcane
(C) Cauliflower, onion, potato and tomato
(D) Lady’s finger, onion, ginger and sugarcane
Answer:
(B) Potato, ginger, onion and sugarcane

Explanation:
Potato, ginger, onion, and sugarcane exhibit vegetative reproduction.

Question 11.

In a flower, the parts that produce male and female gametes (germ cells) are

(A) stamen and anther
(B) filament and stigma
(C) anther and ovary
(D) stamen and style
Answer:
(C) anther and ovary

Explanation:
In a flower, pollen grains are formed inside the anther, which produces the male gametes while the ovary bears the female gamete.

Question 12.

Which of the following is the correct sequence of events of sexual reproduction in a flower?

(A) Pollination, fertilisation, seedling, embryo
(B) Seedling, embryo, fertilisation, pollination
(C) Pollination, fertilisation, embryo, seedling
(D) Embryo, seedling, pollination, fertilisation
Answer:
(C) Pollination, fertilisation, embryo, seedling

Explanation:
The correct sequence of events of sexual reproduction in a flower is pollination, fertilization, embryo, seedling. Pollination is the process of transfer of pollens from stamen to stigma after which fertilization takes place, during which germ cells fuse together to form zygote which in turn leads to embryo formation within the ovule. Fertilized ovule becomes seed and seeds germinate to produce seedling.

Question 13.

The correct sequence of reproductive stages seen in flowering plants is

(A) gametes, zygote, embryo, seedling
(B) zygote, gametes, embryo, seedling
(C) seedling, embryo, zygote, gametes
(D) gametes, embryo, zygote, seedling
Answer:
(A) gametes, zygote, embryo, seedling

Explanation:
Gamete formation is followed by pollination and fertilization to produce zygote which in turn leads to embryo formation. Fertilized ovule become seed and seeds germinate to produce seedling.

Question 14.

Which of the following statements are true for flowers?

(i) Flowers are always bisexual.
(ii) They are the sexual reproductive organs.
(iii) They are produced in all groups of plants.
(iv) After fertilisation they give rise to fruits.

(A) (i) and (iv)
(B) (ii) and (iii)
(C) (i) and (iii)
(D) (ii) and (iv)
Answer:
(D) (ii) and (iv)

Explanation:
Flowers are the sexual reproductive organs of a plant and a fertilized flower gives rise to fruit.

Question 15.

A student while observing an embryo of a gram seed listed various parts of the embryo as listed below: Testa, Micropyle, Cotyledon, Tegmen, Plumule, Radicle. On examining the list the teacher commented that only three parts are correct. Select these three correct parts:

(A) Cotyledon, Testa, Plumule
(B) Cotyledon, Plumule, Radicle
(C) Cotyledon, Tegmen, Radicle
(D) Cotyledon, Micropyle, Plumule
Answer:
(B) Cotyledon, Plumule, Radicle

Explanation:
When a plant produces a seed, it has basic parts: plumule (the future shoot), radicle (the future root) and the cotyledons which may be 2 or 1 based on the type of plant being it dicot or monocot, respectively.

Question 16.

Characters that are transmitted from parents to offspring during reproduction show

(A) only similarities with parents
(B) only variations with parents
(C) both similarities and variations with parents
(D) neither similarities nor variations
Answer:
(C) both similarities and variations with parents

Explanation:
Meiosis during gamete formation and fertilization produce variations while DNA replication ensures similarities.

Question 17.

Length of pollen tube depends on the distance between

(A) pollen grain and upper surface of stigma
(B) pollen grain on upper surface of stigma and ovule
(C) pollen grain in anther and upper surface of stigma
(D) upper surface of stigma and lower part of style
Answer:
(B) pollen grain on upper surface of stigma and ovule

Explanation:
Pollen tube carries male gametes to ovule and thus, is long equal to the distance between stigma and ovary.

Question 18.

The number of chromosomes in parents and offsprings of a particular species remains constant due to

(A) doubling of chromosomes after zygote formation
(B) halving of chromosomes during gamete formation
(C) doubling of chromosomes after gamete formation
(D) halving of chromosomes after gamete formation
Answer:
(B) halving of chromosomes during gamete formation

Explanation:
Meiosis reduces the chromosome number to half which is then restored by fertilization.

Question 19.

During adolescence, several changes occur in the human body. Mark one change associated with sexual maturation in boys.

(A) Loss of milk teeth
(B) Increase in height
(C) Cracking of voice
(D) Weight gain
Answer:
(C) Cracking of voice

Explanation:
Cracking of voice is one of the secondary sexual characters of human males observed during adolescence.

Question 20.

In human females, an event that reflects onset of reproductive phase is

(A) growth of body
(B) changes in hair pattern
(C) change in voice
(D) menstruation
Answer:
(D) menstruation

Explanation:
Development of female secondary sexual characters marks onset of puberty and initiation of menstrual cycle reflects onset of reproductive phase.

Question 21.

In human males, the testes lie in the scrotum, because it helps in the

(A) process of mating.
(B) formation of sperm.
(C) easy transfer of gametes.
(D) all of the above.
Answer:
(B) formation of sperm.

Explanation:
Scrotum provides lower temperature needed for sperm formation.

Question 22.

Which among the following is not the function of testes at puberty?

(i) Formation of germ cells
(ii) Secretion of testosterone
(iii) Development of placenta
(iv) Secretion of estrogen

(A) (i) and (ii)
(B) (ii) and (iii)
(C) (iii) and (iv)
(D) (i) and (iv)
Answer:
(C) (iii) and (iv)

Explanation:
Development of placenta and secretion of estrogen are female reproductive functions.

Question 23.

Which of these statement is correct about reproduction ?

(A) It keeps the individual organism alive
(B) It fulfills their energy requirement
(C) It maintains the growth
(D) It continue the species generation after generation
Answer:
(D) It continue the species generation after generation

Explanation:
Reproduction serves to continue the species which would otherwise extinct due to struggle for survival and natural accidental death of individuals.

Question 24.

The correct sequence of organs in the male reproductive system for transport of sperms is

(A) testis → vas deferens → urethra
(B) testis → ureter → urethra
(C) testis → urethra → ureter
(D) testis → vas deferens → ureter
Answer:
(A) testis → vas deferens → urethra

Explanation:
Vas deferens delivers sperms from testes to urethra coming from the urinary bladder.

Question 25.

Which among the following diseases is not sexually transmitted?

(A) Syphilis
(B) Hepatitis
(C) HIV – AIDS
(D) Gonorrhoea
Answer:
(B) Hepatitis

Explanation:
Hepatitis is water borne viral disease.

Question 26.

Which of the following is not a part of the female reproductive system in human beings?

(A) Ovary
(B) Uterus
(C) Vas deferens
(D) Fallopian tube
Answer:
(C) Vas deferens

Explanation:
Vas deferens is not a part of the female reproductive system in human beings.

Assertion and Reason Based MCQs
Directions : In the following questions, A statement of Assertion (A) is followed by a statement of Reason (R). Mark the correct choice as.

(A) Both A and R are true and R is the correct explanation of A.
(B) Both A and R are true but R is NOT the correct explanation of A.
(C) A is true but R is false.
(D) A is false and R is true.

Question 1.

Assertion (A): Amoeba reproduces by binary fission.
Reason (R): All unicellular organisms reproduce asexually.

Answer:
(A) Both A and R are true and R is the correct explanation of A.

Explanation:
Amoeba is a unicellular organism. It reproduces asexually through binary fission. It is the division of one cell into two similar or identical cells.

Question 2.

Assertion (A): Plants are vegetatively propagated even though they bear seeds.
Reason (R): Potatoes reproduces through tubers, apples by cutting etc.

Answer:
(B) Both A and R are true but R is NOT the correct explanation of A.

Explanation:
Vegetative reproduction happens through the use of vegetative parts of the plants, such as leaves, stems, and roots to produce new plants or through growth from specialized vegetative plant parts.

Question 3.

Assertion (A): Characteristics of parental plants can be preserved through asexual reproduction.
Reason (R): Vegetative reproduction involves only mitosis.

Answer:
(A) Both A and R are true and R is the correct explanation of A.

Explanation:
Asexual reproduction involves a single individual, which give rise to new individual that are genetically identical to parents. It is because, when organisms reproduce asexually, only mitotic divisions are involved and the chromosome number remains the same.

Question 4.

Assertion (A): Plasmodium reproduces by multiple fission.
Reason (R): Multiple fission is a type of asexual reproduction.

Answer:
(B) Both A and R are true but R is NOT the correct explanation of A.

Explanation:
Plasmodium reproduces asexually by multiple fission.

Question 5.

Assertion (A): DNA copying is necessary during reproduction.
Reason (R): DNA copying leads to the transmission of characters from parents to offspring.

Answer:
(A) Both A and R are true and R is the correct explanation of A.

Explanation:
DNA copying is necessary during reproduction because it leads to the transmission of characters from parents to offsprings and brings about variation.

Question 6.

Assertion (A): An embryo is formed from fertilized egg
Reason (R): A monocot embryo comprises embryo¬nal axis with two cotyledons.

Answer:
(C) A is true but R is false.

Explanation:
Zygote, a fertilized egg give rise to an embryo, which has the ability to develop into a complete plant. A typical dicot embryo comprises an embryonal axis with two cotyledons.

Question 7.

Assertion (A): Unisexual flowers have separate male and female flowers whereas a typical monocot embryo comprises an embryonal axis with single cotyledon.
Reason (R): Cucumber, pumpkin and water melon are example of unisexual flowers.

Answer:
(B) Both A and R are true but R is NOT the correct explanation of A.

Explanation:
Unisexual flowers have separate male and female flowers. The example includes cucumber, pumpkin and watermelon.

Question 8.

Assertion (A): Double fertilisation is unique to angiosperms.
Reason (R): Triple fusion occurs in asexual repro-duction.

Answer:
(C) A is true but R is false.

Explanation:
Double fertilization is a characteristic feature of flowering plants. In this process, out of the two sperm nuclei, one sperm nucleus fuses with the egg nucleus to form an embryo (process is called syngamy) and another fuses with the secondary nucleus to form an endosperm (process is called triple fusion). Because two kinds of fusion syngamy and triple fusion take place, the process is known as double fertilisation.

Question 9.

Assertion: Fertilization results in formation of zygote.
Reason: Zygote divides several times to form an embryo.

Answer:
(B) Both A and R are true but R is NOT the correct explanation of A.

Explanation:
Fertilization is a process which involves fusion of male and female germ cells to form zygote. This zygote divides several times to form an embryo. The ovule develops a thick coat and changes into seed. The ovary grows rapidly and ripens to form the fruit.

Question 10.

Assertion (A): Sexual reproduction increases genetic diversities and plays a role in origin of new species.
Reason (R): Sexual reproduction involves formation of gametes and fusion of gametes.

Answer:
(A) Both A and R are true and R is the correct explanation of A.

Explanation:
Sexual reproduction involves two parents that results in the offsprings that are not identical to the parents. It causes variations; which are essential for evolution as well as survival of species under unfavourable conditions.

Question 11.

Assertion (A): In human male, testes are extra-abdominal organs which are present inside scrotum. Reason (R): Scrotum has a relatively lower temperature needed for the production and storage of sperms.

Answer:
(A) Both A and R are true and R is the correct explanation of A.

Explanation:
Formation of sperm needs lower temperature than the normal body temperature. Hence, testes lie outside the body cavity in the scrotum.

Question 12.

Assertion (A): At puberty, in boys, voice begins to crack and thick hair grows on face.
Reason (R): At puberty, there is decreased secretion of testosterone in boys.

Answer:
(C) A is true but R is false.

Explanation:
Puberty in boys is regulated by male sex hormone called testosterone, which are secreted by testes. In puberty, secondary sexual characters like growth of hair on face, chest, broadening of shoulders and deepening of voice occurs.

Question 13.

Assertion (A): Surgical methods are most effective methods of contraception.
Reason (R): Surgical method blocks gametes transport and hence prevent fertilisation.

Answer:
(A) Both A and R are true and R is the correct explanation of A.

Explanation:
Surgical method like vasectomy in male and tubectomy in female prevent pregnancy. These methods block gamete transport and hence prevent fertilisation. They are very effective but reversibility is very poor.

Case-Based MCQs

Attempt any 4 sub-parts from each question. Each sub-part carries 1 mark.
I. Read the following passage and answer any four questions from Question 1. to Question 5.
The growing size of the human population is a cause of concern for all people. The rate of birth and death in a given population will determine its size. Reproduction is the process by which organisms increase their population. The process of sexual maturation for reproduction is gradual and takes place while general body growth is still going on. Some degree of sexual maturation does not necessarily mean that the mind or body is ready for sexual acts or for having and bringing up children. Various contraceptive devices are being used by human beings to control the size of population.

Question 1.

What are common signs of sexual maturation in boys is:

(A) Broadening of shoulders
(B) Development of mammary glands
(C) Broadening of waist
(D) High pitch of voice
Answer:
(A) Broadening of shoulders

Explanation:
Development of mammary glands or breast, broadening of waist and high pitch of voice are the characters of maturation in female

Question 2.

Common sign of sexual maturation in girls is:

(A) Low pitch voice
(B) Appearance moustache and beard
(C) Development of mammary gland
(D) Broadening of shoulders
Answer:
(C) Development of mammary gland

Explanation:
Development of mammary gland is the character of female maturation while Low pitch voice, appearance of moustache and beard, broadening of shoulders

Question 3.

Which contraceptive method changes the hormonal balance of the body?

(A) Condoms
(B) Diaphragms
(C) Oral pills
(D) Both (a) and (b)
Answer:
(C) Oral pills

Explanation:
Oral pills are responsible to prevent ovulation in the female body by hotmonal change while condoms and diaphragm are only contraceptive barrier that doesn’t bring any hormonal changes.

Question 4.

Write two factors that determine the size of a population.

Answer:
Factors are: Birth rate and death rate.

Question 5.

What should be maintained for a healthy society?

(A) rate of birth & death rate
(B) male & female sex ratio
(C) child sex ratio
(D) None of these
Answer:
(B) male & female sex ratio

II. Study the diagram given below and answer any four questions from Question 1. to Question 5.

Question 1.

Identify the above process.

(A) Binary fission
(B) Budding
(C) Fragmentation
(D) Regeneration
Answer:
(B) Budding

Explanation:
Budding is a type of asexual reproduction wherein a daughter organism is formed from a small projection known as bud.

Question 2.

Which organism uses the above method for reproduction?

(A) Yeast
(B) Amoeba
(C) Spirogyra
(D) Leishmania
Answer:
(A) Yeast

Explanation:
Yeast reproduces asexually by budding.
Question 3.

An organism capable of reproducing by two asexual reproduction methods one similar to the reproduction in yeast and the other similar to the reproduction in Planaria is:

(A) Spirogyra
(B) Hydra
(C) Bryophyllum
(D) Paramecium
Answer:
(B) Hydra

Explanation:
Hydra reproduces asexually by budding (as yeast) and by regeneration (as Planaria).

Question 4.

A Planaria worm is cut horizontally in the middle into two halves P and Q such that the part P contains the whole head of the worm. Another Planaria worm is cut vertically into two halves R and S in such a way that both the cut pieces R and S contain half head each. Which of the cut pieces of the two Planaria worms could regenerate to form the complete respective worms?

(A) Only P
(B) Only R and S
(C) P, Rand S
(D) P, Q, R and S
Answer:
(D) P, Q, R and S

Explanation:
Planaria reproduces asexually by regeneration. It is the ability of a fully differentiated organism to give rise to new individual organisms from its body parts. Small cut or broken parts of the organism’s body grow or regenerate into separate individuals.

Question 5.

Among the following select the statements that are true regarding the sexual reproduction in flowering plants?

(1) Fertilisation is a compulsory event
(2) It always results in the formation of zygote
(3) Offsprings formed are clones
(4) It requires two types of gametes

(A) (1) and (4)
(B) (1), (2) and (3)
(C) (1), (2) and (4)
(D) (2), (3) and (4)
Answer:
(B) (1), (2) and (3)

Explanation:
Sexual reproduction in flowers require two types of gametes. The fusion of gametes results in the formation of the zygote. This process is termed as fertilisation.

III. Study the process depicted in the picture given below and answer any four question from Question 1. to Question 5.

1. Parent cell
2. Nucleus divides
3. Cytoplasm divides
4. Two daughter cells

Question 1.

Which of these organisms divides by the above process?

(A) Amoeba
(B) Spirogyra
(C) Leishmania
(D) Yeast
Answer:
(A) Amoeba

Explanation:
Amoeba reproduces asexually by binary fission. It is the division of one cell into two similar or identical cells. The nucleus first divides amitotically into two, followed by the . division of the cytoplasm. The cell finally splits into two daughter cells.

Question 2.

In multiple fission :

(A) Two daughter cells are produced.
(B) Many daughter cells are formed simultaneously.
(C) Two types of gametes fuse together
(D) None of these
Answer:
(B) Many daughter cells are formed simultaneously.

Explanation:
Binary fission: Two daughter cells are produced. Multiple fission: Many daughter cells are formed simultaneously.

Question 3.

Which of the following statement is correct about the above type of reproduction?

(A) It involves two individuals.
(B) It involves a mature parent cell.
(C) It involves union of two types of gametes.
(D) All of these
Answer:
(B) It involves a mature parent cell.

Explanation:
Asexual reproduction involves a single parent.

Question 4.

Which of these statement is correct about the fission in Leishmanial

(A) Splitting into two cells during division can take place in any plane.
(B) Binary fission occurs in a definite orientation in relation to the whip like structure.
(C) Both of these
(D) None of these
Answer:
(B) Binary fission occurs in a definite orientation in relation to the whip like structure.

Explanation:
In Amoeba, splitting into two cells during division can take place in any plane. In Leishmania, binary fission occurs in a definite orientation in relation to the whip like structure.

Question 5.

Which of these are the characteristics of vegetative reproduction?

(i) Involves two individuals
(ii) Daughter cells are genetically identical to the parent.
(iii) The cell division is only mitotic.

(A) (i) and (ii) only
(B) (i) and (iii) only
(C) (ii) and (iii) only
(D) All of these
Answer:
(C) (ii) and (iii) only

Explanation:
The characteristic features of vegetative reproduction are: cell division take place by mitosis and daughter cells formed are genetically identical to the parent.

IV. Study the given diagram and answer any four questions from Question 1. to Question 5 as given below:

Question 1.

The above diagram depicts:

(A) Spore formation in Rhizopus
(B) Fragmentation in Spirogyra
(C) Binary fission in Amoeba
(D) Spore formation in Yeast
Answer:
(A) Spore formation in Rhizopus

Explanation:
Spore formation takes place in Rhizopus.

Question 2.

‘Blobs’ that develop at the tips of the non- reproductive thread is known as :

(A) Hyphae
(B) Sporangia
(C) Spores
(D) Pollens
Answer:
(B) Sporangia

Explanation:
Rhizopus consists of fine thread like projection called hyphae. It has a knob like structure which is involved in reproduction called sporangia. Each sporangium contains hundreds of black spores which gets dispersed into air to germinate on suitable substratum.

Question 3.

The thread like non-reproductive structures is :

(A) Hyphae
(B) Rhizoids
(C) Sporangium
(D) Sporangiophores
Answer:
(A) Hyphae

Explanation:
Rhizopus consists of fine thread like projection called hyphae.

Question 4.

On maturation sporangia of given organism bursts and releases :

(A) Pollens
(B) Spores
(C) Seeds
(D) None of these
Answer:
(B) Spores

Explanation:
On maturation sporangia of given organism bursts and releases spores. They germinate into new individuals under favourable conditions.

Question 5.

Which of these plants reproduces in the same way as the given process?

(A) Balsam
(B) Fern
(C) Mango
(D) Hibiscus
Answer:
(B) Fern

Explanation:
Fern reproduces by spores.

V.The given diagram represent the structure of a flower. Study the structure and answer any four questions from Question 1. to Question 5.

Question 1.

The labels A, B and C are

(A) Anther, Style and Ovary respectively.
(B) Stamen, Stigma and Ovule respectively.
(C) Anther, Style and Stigma respectively.
(D) Stamen, Fragment and Ovary respectively.
Answer:
(A) Anther, Style and Ovary respectively.

Explanation:
In the given picture, A represents anther, B represents style and C represent ovary.

Question 2.

Which of these is the function of part labelled as C?

(A) Contains ovules which develop into seeds.
(B) Attracts pollinators.
(C) Protect rising buds.
(D) Receive pollens
Answer:
(A) Contains ovules which develop into seeds.

Explanation:
The part labelled as C is Ovary. Ovary contains ovule which develops into seeds while ovary forms the fruit.

Question 3.

When an insect sits on the flower of a plant then some particles from the little stalks in the flowers sticks to its body and when this insect sits on the flower of another plant, the particles get deposited in that flower. What are these particles?

(A) Dust
(B) Pollens
(C) Grains
(D) Seeds
Answer:
(B) Pollens

Explanation:
Pollen is a powdery substance consisting of pollen grains which are male microgametophytes of seed plants, which produce male gametes (sperm cells).

Question 4.

A student decides to study the impact of removing certain flower parts on fruit formation in plant species X. He chooses three separate plants that are growing in the same plot under uniform conditions. The data is given in the table below.

Plants	Part Removed	Impact on formation
1.	Anther	30% less fruit formed than average plants in the plot
2.	Stigma	No fruit formed
3.	Petal	No significant impact

Which of the following can be inferred from the above data?

(A) Anthers and stigmas are crucial in sexual reproduction in species X.
(B) Pollen grains are probably unable to germinate if they land on other parts of the carpel besides the stigma.
(C) Species X is likely to be wind-pollinated.
(D) Species X relies completely on cross pollination.
Answer:
(C) Species X is likely to be wind-pollinated.

Explanation:
The removal of anthers affects fruit formation in plant this implies that species X relies partially on self-pollination. The removal of either anthers or stigmas affects rate of fruit formation significantly. No fruits are observed when the stigmas in plant 2 are removed. This shows that pollen grains are probably unable to germinate if they land on any other part of the carpel besides the stigma. The petals do not seem to play a significant role in facilitating fruit formation. Species-X is therefore likely to be wind-pollinated with reduced petals.

Question 5.

Which of these events does not take place after fertilisation ?

(A) Formation of zygote.
(B) Development of thick coat around ovule.
(C) Ovary ripens to form fruit.
(D) Transfer of pollen from anther to stigma of a flower.
Ans.
(D) Transfer of pollen from anther to stigma of a flower.

Explanation:
Fertilization results in formation of zygote. Zygote divides several times, to form an embryo. The ovule develops a thick coat and is developed into seed. The ovary grows rapidly and ripens to form the fruit.

VI. Study the diagram given below and answer any four questions from Question 1. to Question 5

Question 1.

The part labelled as A in the diagram is:

(A) Dust
(B) Germs
(C) Pollen
(D) Pollinators
Answer:
(C) Pollen

Explanation:
The part labelled as A is pollen pollen grain.

Question 2.

Which of the following statement is incorrect about pollination?

(A) It precedes fertilization.
(B) It follows fertilization.
(C) It brings male and female gametes closer.
(D) It introduces variations in plants.
Answer:
(B) It follows fertilization.

Explanation:
Fertilization which involves fusion of male and female germ cells can only occur only after pollination.

Question 3.

The importance of the part “C” is :

(A) It carries female gametes.
(B) It carries male gametes.
(C) It carries food for the seeds.
(D) None of these
Answer:
(B) It carries male gametes.

Explanation:
It (pollen tube) carries male gamete to reach egg in embryo sac in ovule

Question 4.

What happens to the part marked ‘D’ after fertilization is over?

(A) Converted into seed.
(B) Converted into fruit
(C) Converted into embryo
(D) Converted into flower.
Answer:
(C) Converted into embryo

Explanation:
The part maked ‘D’ is ovule. Flowering plants (angiosperms) create embryos after the fertilization of a haploid ovule by pollen. The DNA from the ovule and pollen combine to form a diploid, single-cell zygote that will develop into an embryo.

Question 5.

Choose the incorrect statements about the reproductive system of a plant?

(A) The male organs are the stamens.
(B) The anthers produce female gametes.
(C) The male gametes are present in the pollen grains.
(D) A male gamete from a pollen grain fertilize a female gamete in an ovule.
Answer:
(B) The anthers produce female gametes.

Explanation:
In a flower, the male reproductive parts are anthers which produce the male gametes.

VII. Study the diagram given below and answer any four questions from Question 1. to Question 5.

Question 1.

The part labelled as A is:

(A) Dust
(B) Germs
(C) Pollen
(D) Pollinators
Answer:
(C) Pollen

Explanation:
The part labelled as A is male germ cells (pollen grain).

Question 2.

The role of part labelled as B is:

(A) Transport of male gametes to the ovary.
(B) Transport of female gametes to the ovary
(C) Contains ovules which develop into seeds.
(D) All of these
Answer:
(A) Transport of male gametes to the ovary.

Explanation:
Style facilitate the transport of the male gametes to the ovary.

Question 3.

How many male gametes are produced by each pollen grain?

(A) One
(B) Two
(C) Three
(D) Four
Answer:
(B) Two

Explanation:
Each pollen grain produces two 1 male gametes.

Question 4.

What happens to the label A which falls on a suitable stigma?

(A) Pollen grain gradually disintegrates.
(B) Pollen grain directly reaches the embryo sac.
(C) Pollen grain starts germinating and forms a pollen tube.
(D) Pollen grain changes into ovules and then to fruit.
Answer:
(C) Pollen grain starts germinating and forms a pollen tube.

Explanation:
The part labelled A is pollen. The pollen grain starts germinating and forms a pollen tube. The pollen tube grows into the style till it reaches the ovule through micropyle. The pollen tube then reaches the embryo sac into which it releases the two male gametes contained in it. The male gamete then fuses with the female gamete in the embryo sac.

Question 5.

In the given diagram showing the carpel of an insect pollinated flower, the most likely reason for the non-germination of pollen grain Z is :X

(A) Pollen grains X and V were brought to the stigma earlier, therefore, their germination inhibited the germination of pollen grain Z.
(B) Pollen grain Z was brought to the flower by wind, while pollen grains X and Y were brought to the flower by insects.
(C) Pollen grain Z lacks protrusions that allow it to adhere properly onto the stigma surface.
(D) Pollen grain Z comes from a flower of an incompatible species.
Answer:
(D) Pollen grain Z comes from a flower of an incompatible species.

Explanation:
Pollen grains can only germinate if the pollen grain and stigma are compatible, i.e., of the same or closely related species. Pollen grains X and Y must have come from a compatible species. Only compatible pollen grains germinate and form pollen tubes

MCQ Questions for Class 10 Science with Answers

MCQ Questions for Class 10 Science Chapter 8 How do Organisms Reproduce? Read More »

Author name: Prasanna

MCQ Questions for Class 10 Science Chapter 13 Magnetic Effects of Electric Current

Magnetic Effects of Electric Current Class 10 MCQ Questions With Answers

Choose the incorrect statement from the following regarding magnetic lines of field :

Which of the following correctly describes the magnetic field near a long straight current carrying wire?

A constant current flowing in a horizontal wire in the plane of the paper from East to West is shown in Figure. The direction of magnetic field at a point will be from North to South :

If the key in the arrangement in the given Figure, is taken out (the circuit is made open) and magnetic field lines are drawn over the horizontal plane ABCD, the lines are:

For a current in a long straight solenoid N- and S-poles are created at the two ends. Among the following statements, the incorrect statement is :

The strength of magnetic field inside a long current carrying straight solenoid is :

Which of the following property of a proton can change while it moves freely in a magnetic field? (There may be more than one correct answer.)

A positively-charged particle (alpha – particle pro-jected towards west is deflected towards north by a magnetic field. The direction of magnetic field is

The phenomenon of electro-magnetic induction is :

The essential difference between an AC generator and a DC generator is that:

Choose the correct option. A rectangular coil of copper wires is rotated in a magnetic field. The direction of the induced current changes once in each:

Choose the incorrect statement:

At the time of short circuit, the current in the circuit:

The most important safety method used for protecting home appliances from short circuiting or overloading is :

Assertion (A): Two bar magnets attract when they are brought near to each other with the same pole. Reason (R): Unlike poles will attract each other.

Assertion (A): Magnetic field lines never intersect. Reason (R): At a particular point magnetic field has only one direction.

Assertion (A): In Fleming’s Left Hand Rule, the direction of magnetic field, force and current are mutually perpendicular. Reason (R): Fleming’s Left hand Rule is applied to measure the induced current.

Assertion (A): An alpha particle placed in a magnetic field will not experience any force, if it moves in the magnetic field parallel to field lines. Reason (R): The force is zero if current and field are in the same direction.

Assertion (A): Safety fuses are made up of materials having a low melting point. Reason (R): Safety fuses should be resistant to electric current.

Assertion (A): Copper is used to make electric wires. Reason (R): Copper has very low electrical resistance.

Assertion (A): When two bulbs are operated on same voltage supply, having power 60 W and 100 W then 100 W bulb has less resistance than 60 W. Reason (R): The power of the bulb is directly proportional to the square of the voltage.

What type of energy conversion is observed in a linear solenoid?

What will happen if a soft iron bar is placed inside the solenoid?

The magnetic field lines produced inside the solenoid are similar to that of… A

After analysing the graph a student writes the following statements.

From the graph deduce which of the following statements is correct ?

A momentary deflection is shown by the galvanometer, when:

Which phenomenon is involved in it ?

In above phenomenon, the current is induced in another conductor,

The rule which helps us to know direction of induced current:

Flemings right hand rule explains:

Why do the iron fillings arrange themselves in a particular pattern ?

What do the lines along which the iron fillings align represent ?

What does the crowding of iron filings at the end of the magnet indicate?

The closer field lines indicate:

What is SI unit of magnetic field:

MCQ Questions for Class 10 Science with Answers

MCQ Questions for Class 10 Science Chapter 12 Electricity

Electricity Class 10 MCQ Questions With Answers

A cylindrical conductor of length T and uniform area of cross section A’ has resistance ‘R’. The area of cross section of another conductor of same material and same resistance but of length ’21’ is

The maximum resistance which can be made using four resistor each of resistance \(\frac{1}{2} Ω\) is

When a 4V battery is connected across an unknown resistor there is a current of 100 mA in the circuit. The value of the resistance of the resistor is:

Unit of electric power may also be expressed as:

A cell, a resistor, a key, and ammeter are arranged as shown in the circuit diagrams given below. The current recorded in the ammeter will be:

Electrical resistivity of a given metallic wire depends upon

A current of A is drawn by a filament of an electric bulb. Number of electrons passing through a cross section of the filament in 16 seconds would be where, e = 1.6 x 10-19 C

The resistivity does not change if :

Two bulbs of 100 W and 40 W are connected in series. The current through the 100 W bulb is 1 A. The current through the 40 W bulb will be:

What is the maximum resistance which can be made using five resistors each of \(\frac{1}{5}\)Ω ?

What is the minimum resistance which can be made using five resistors each of \(\frac{1}{5}\)Ω ?

Which of the following represents voltage?

If the current through a resistor is increased by 100% (assume that temperature remains unchanged), the increase in power dissipated will be

In an electrical circuit three incandescent bulbs A, B, and C of rating 40 W, 60 W, and 100 W, respec¬tively are connected in parallel to an electric source. Which of the following is likely to happen regard¬ing their brightness?

An electric kettle consumes 1 kW of electric power when operated at 220 V. A fuse wire of what rating must be used for it?

Assertion (A): A conductor has + 3.2 x 1019 C charge. Reason (R): Conductor has gained 2 electrons.

Assertion (A): The resistivity of conductor increases with the increasing of temperature. Reason (R): The resistivity is the reciprocal of the conductivity.

Assertion (A): Bending a wire does not affect electrical resistance. Reason (R): Resistance of wire is proportional to resistivity of material.

Assertion (A): Two resistance having value R each. Their equivalent resistance is\(\frac{R}{2}\). Reason (R): Given Resistances are connected in parallel.

Assertion (A): Alloys are commonly used in electrical heating devices like electric iron and heater. Reason (R): Resistivity of an alloy is generally higher than that of its constituent metals but the alloys have low melting points then their constituent metals.

Assertion (A): In a simple battery circuit the point of lowest potential is positive terminal of the battery. Reason (R): The current flows towards the point of the lower potential as it flows in such a circuit from the positive to the negative terminal.

Assertion (A): Electric appliances with metallic body have three connections, whereas an electric bulb has a two pin connection. Reason (R): Three pin connections reduce heating of connecting wires.

Assertion (A): The electric bulbs glow immediately when switch is ON. Reason (R): The drift velocity of electrons in a metallic wire is very high.

Assertion (A): Copper is used to make electric wires. Reason (R): Copper has very low electrical resistance.

Assertion (A): Silver is not used to make electric wires. Reason (R): Silver is a bad conductor.

Which of the following is the correct circuit diagram to connect all the devices in proper correct order.

How much is the total resistance?

Two students perform experiments on two given resistors R1 and R2 and plot the following V-I graphs. If R1 > R2 which of the diagrams correctly

The device used to measure the current:

Which of the following is connected in series in circuit:

Which is a better conductor ?

Element used to make heating element of electric geyser:

Element used to make filament of incandescent bulb:

What happens to resistance of a conductor when its area of cross section is increased?

A given length of a wire is doubled and this process is repeated once again. The resistance of wire becomes:

Which is a better conductor of electric current ?

Which element will be used for electrical transmission lines ?

Nichrome is used in the heating elements of electric heating device because:

Assertion (A): Two bar magnets attract when they are brought near to each other with the same pole.
Reason (R): Unlike poles will attract each other.

Assertion (A): Magnetic field lines never intersect.
Reason (R): At a particular point magnetic field has only one direction.

Assertion (A): In Fleming’s Left Hand Rule, the direction of magnetic field, force and current are mutually perpendicular.
Reason (R): Fleming’s Left hand Rule is applied to measure the induced current.

Assertion (A): An alpha particle placed in a magnetic field will not experience any force, if it moves in the magnetic field parallel to field lines.
Reason (R): The force is zero if current and field are in the same direction.

Assertion (A): Safety fuses are made up of materials having a low melting point.
Reason (R): Safety fuses should be resistant to electric current.

Assertion (A): Copper is used to make electric wires.
Reason (R): Copper has very low electrical resistance.

A current of A is drawn by a filament of an electric bulb. Number of electrons passing through a cross section of the filament in 16 seconds would be where, e = 1.6 x 10^-19 C

Assertion (A): A conductor has + 3.2 x 10₁₉ C charge.
Reason (R): Conductor has gained 2 electrons.

Assertion (A): The resistivity of conductor increases with the increasing of temperature.
Reason (R): The resistivity is the reciprocal of the conductivity.

Assertion (A): Bending a wire does not affect electrical resistance.
Reason (R): Resistance of wire is proportional to resistivity of material.

Assertion (A): Two resistance having value R each. Their equivalent resistance is\(\frac{R}{2}\).
Reason (R): Given Resistances are connected in parallel.

Assertion (A): Alloys are commonly used in electrical heating devices like electric iron and heater.
Reason (R): Resistivity of an alloy is generally higher than that of its constituent metals but the alloys have low melting points then their constituent metals.

Assertion (A): In a simple battery circuit the point of lowest potential is positive terminal of the battery.
Reason (R): The current flows towards the point of the lower potential as it flows in such a circuit from the positive to the negative terminal.

Assertion (A): Electric appliances with metallic body have three connections, whereas an electric bulb has a two pin connection.
Reason (R): Three pin connections reduce heating of connecting wires.

Assertion (A): The electric bulbs glow immediately when switch is ON.
Reason (R): The drift velocity of electrons in a metallic wire is very high.

Assertion (A): Copper is used to make electric wires.
Reason (R): Copper has very low electrical resistance.

Assertion (A): Silver is not used to make electric wires.
Reason (R): Silver is a bad conductor.

Two students perform experiments on two given resistors R₁ and R₂ and plot the following V-I graphs. If R₁ > R₂ which of the diagrams correctly

What will happen to the other two bulbs if the bulb B₃ gets fused ?

Difference in reading of ammeter A₁ and A₂

Study the following ray diagram :

In this diagram, the angle of incidence, the angle of emergence and the angle of deviation respectively have been represented by

Assertion (A): A white light on passing through prism splits into its component colours as such that the red light emerges nearest to the base of the prism.
Reason (R): Wavelength of red light is more than other component colours and hence, red light deviates least.

Assertion (A): In case of rainbow, light at the inner surface of the water drop gets internally reflected.
Reason (R): The angle between the refracted ray and normal to the drop surface is greater than the critical angle.

Assertion (A): Scattering of light is the reflection of light from an object in all directions.
Reason (R): The colour of scattered light depends on the size of scattering particles and wavelength of light.

In your laboratory you trace the path of light rays through a glass slab for different values of angle of incidence (∠i) and in each case measure the values of the corresponding angle of refraction (∠r) and angle of emergence (∠e).
On the basis of your observation your correct conclusion is: