{"id":28471,"date":"2022-06-04T17:30:39","date_gmt":"2022-06-04T12:00:39","guid":{"rendered":"https:\/\/mcq-questions.com\/?p=28471"},"modified":"2022-05-23T15:22:42","modified_gmt":"2022-05-23T09:52:42","slug":"ncert-solutions-for-class-10-science-chapter-10","status":"publish","type":"post","link":"https:\/\/mcq-questions.com\/ncert-solutions-for-class-10-science-chapter-10\/","title":{"rendered":"NCERT Solutions for Class 10 Science Chapter 10 Light Reflection and Refraction"},"content":{"rendered":"

These NCERT Solutions for Class 10 Science<\/a> Chapter 10 Light Reflection and Refraction Questions and Answers are prepared by our highly skilled subject experts to help students while preparing for their exams.<\/p>\n

Light Reflection and Refraction NCERT Solutions for Class 10 Science Chapter 10<\/h2>\n

Class 10 Science Chapter 10 Light Reflection and Refraction InText Questions and Answers<\/h3>\n

In-text Questions (Page 168)<\/span><\/p>\n

Question 1.
\nDefine the principal focus of a concave mirror.
\nAnswer:
\nA point on the principal axis at which all parallel rays to the principal axis meets is called the principal focus of the concave mirror.<\/p>\n

Question 2.
\nThe radius of curvature of a spherical mirror is 20 cm. What is its focal length?
\nAnswer:
\nFocal length (l)
\n\"NCERT<\/p>\n

Question 3.
\nName a mirror that can give an erect and enlarged image of an object.
\nAnswer:
\nConcave mirror.<\/p>\n

Question 4.
\nWhy do we prefer a convex mirror as a rear-view mirror in vehicles?
\nAnswer:
\nConvex mirrors are preferred because they always give an erect, through diminished, image. Also, they have a wider field of view as they are curved outwards.<\/p>\n

\"NCERT<\/p>\n

In-text Questions (Page 171)<\/span><\/p>\n

Question 1.
\nFind the focal length of a convex mirror whose radius of curvature is 32 cm.
\nAnswer:
\nR = 2f
\n\u2234 f = \\(\\frac{R}{2}=\\frac{32 \\mathrm{~cm}}{2}\\) = 16 cm<\/p>\n

Question 2.
\nA concave mirror produces three times magnified (enlarged) real image of an object placed at 10 cm in front of it. Where is the image located?
\nAnswer:
\nMagnification (m) = \\(\\frac{h^{1}}{h}=-\\frac{v}{u}\\)
\n3 = – = \\(-\\frac{v}{(+4)}=-\\frac{v}{4}\\)
\nu = (-3) \u00d7 4 = – 12 cm
\nThe image is located in front of the mirror at 12 cm from the pole of the concave mirror.<\/p>\n

In-text Questions (Page 176)<\/span><\/p>\n

Question 1.
\nA ray of light travelling in air enters obliquely into water. Does the light ray bend towards the normal or away from the normal? Why?
\nAnswer:
\nThe light ray bend towards the normal. When light travels from rarer (air) to denser (water) medium it bends towards the normal.<\/p>\n

Question 2.
\nLight enters from air to glass having refractive index 1.50. What is the speed of light in the glass? The speed of light in vacuum is 3 \u00d7 10s m\/sec.
\nAnswer:
\nThe refractive index of the medium ‘nm’ is given by
\n\"NCERT<\/p>\n

Question 3.
\nFind out, from Table 10.3, the medium having highest optical density. Also find the medium with lowest optical density.
\n\"NCERT
\nAnswer:
\nHigher will be the refractive index, higher will be the optical density of the material and lower refractive index means lower will be the optical density.<\/p>\n

Diamond has the highest optical density (Refractive index 2.42) and air has the lowest optical density, (refractive index 1.0003)<\/p>\n

\"NCERT<\/p>\n

Question 4.
\nYou are given kerosene, turpentine and water. In which of these does the light travel fastest? Use the information given in Table 10.3.
\nAnswer:
\nThe refractive index of kerosene, turpentine and water as follows :
\nKerosene – 1.44
\nWater – 1.33
\nTurpentine – 1.47
\nThe light travel fastest in water because it has lowest refractive index.<\/p>\n

Question 5.
\nThe refractive index of diamond is 2.42. What is the meaning of this statement?
\nAnswer:
\nRefractive index of the medium (or material) is the ratio of the speed of light in air and speed of light in medium S.e.
\n\"NCERT
\nThe refractive index of diamond of means that the ratio of the speed of light in air and the speed of light in diamond is 2.42.<\/p>\n

In-text Questions (Page 184)<\/span><\/p>\n

Question 1.
\nDefine 1 dioptre of power of a lens.
\nAnswer:
\n1 dioptre is the power of a lens whose focal length is 1 metre.<\/p>\n

Question 2.
\nA convex lens forms a real and inverted image of a needle at a distance of 50 cm from it. Where is the needle placed in front of the convex lens if the image is equal to the size of the object? Also, find the power of the lens.
\nAnswer:
\nWe know that
\n\"NCERT
\nDistance of the image from the lens = + 50 cm.
\nNow by lens formula
\n\"NCERT<\/p>\n

Question 3.
\nFind the power of a concave lens of focal length 2 m.
\nAnswer:
\n\"NCERT<\/p>\n

Class 10 Science Chapter 10 Light Reflection and Refraction Textbook Questions and Answers<\/h3>\n

Page no. 185<\/span><\/p>\n

Question 1.
\nWhich one of the following materials cannot be used to make a lens?
\n(a) Water
\n(b) Glass
\n(c) Plastic
\n(d) Clay
\nAnswer:
\n(d) Clay<\/p>\n

Question 2.
\nThe image formed by a concave mirror is observed to be virtual, erect and larger than the object. Where should be the position of the object?
\n(a) Between the principal focus and the centre of curvature
\n(b) At the centre of curvature
\n(c) Beyond the centre of curvature
\n(d) Between the pole of the mirror and its principal focus.
\nAnswer:
\n(d) Between the pole of the mirror and its principal focus.<\/p>\n

\"NCERT<\/p>\n

Question 3.
\nWhere should an object be placed in front of a convex lens to get a real image of the size of the object?
\n(a) At the principal focus of the lens
\n(b) At twice the focal length
\n(c) At infinity
\n(d) Between the optical centre of the lens and its principal focus.
\nAnswer:
\n(b) At twice the focal length<\/p>\n

Question 4.
\nA spherical mirror and a thin spherical lens have each a focal length of -15 cm. The mirror and the lens are likely to be
\n(a) both concave
\n(b) convex
\n(c) The mirror is concave and the lens is convex.
\n(d) The mirror is convex, but the lens is concave.
\nAnswer:
\n(a) Both are concave.<\/p>\n

Question 5.
\nNo matter how far you stand from a mirror, your image appears erect. The mirror is likely to be
\n(a) plane.
\n(b) concave.
\n(c) convex.
\n(d) either plane or convex.
\nAnswer:
\n(c) Convex only<\/p>\n

Question 6.
\nWhich of the following lenses would you prefer to use while reading small letters found in a dictionary?
\n(a) A convex lens of focal length 50 cm.
\n(b) A concave lens of focal length 50 cm.
\n(c) A convex lens of focal length 5 cm.
\n(d) A concave lens of focal length 5 cm.
\nAnswer:
\n(d) A concave lens of focal length 5 cm.<\/p>\n

Question 7.
\nWe wish to obtain an erect image of an object, using a concave mirror of focal length 15 cm. What should be the range of distance of the object from the mirror? What is the nature of the image? Is the image larger or smaller than the object? Draw a ray diagram to show the image formation in this case.
\nAnswer:
\nTo obtain an erect image of an object it should be placed between ‘P’ and ‘F’ i.e., between pole and pricipal focus. So the range of the distance of the object from the mirror will be greater than zero and less than fifteen.<\/p>\n

The image will be virtual and formed behind the mirror. The image is larger than the object.
\n\"NCERT<\/p>\n

Question 8.
\nName the type of mirror used in the following situations.
\n(a) Headlights of a car.
\n(b) Side\/rear-view mirror of a vehicle.
\n(c) Solar furnace.
\nSupport your answer with reason.
\nAnswer:
\n(a) Headlight of a car: Concave mirror is used in head lights of a car to get a powerful parallel beams of light.
\n(b) Side\/rear-view mirror of a vehicle: Convex mirros are commonly used because they always given an erect, through diminished image and they also have a wider field of view.
\n(c) Solar furnace : Large concave mirrors are used in the solar furnace to concentrate sunlight to produce heat in the furnace.<\/p>\n

\"NCERT<\/p>\n

Question 9.
\nOne-half of a convex lens is covered with a black paper. Will this lens produce a complete image of the object? Verify your answer experimentally. Explain your observations.
\nAnswer:
\nWhen one half of a convex lens is covered by a black paper it may or may not be form a complete image. The image formation is based on the position of the object placed in front of the lens.
\nExperimently we observed that.<\/p>\n