{"id":28293,"date":"2021-07-05T11:15:14","date_gmt":"2021-07-05T05:45:14","guid":{"rendered":"https:\/\/mcq-questions.com\/?p=28293"},"modified":"2022-03-02T10:30:22","modified_gmt":"2022-03-02T05:00:22","slug":"ncert-solutions-for-class-8-maths-chapter-12-ex-12-2","status":"publish","type":"post","link":"https:\/\/mcq-questions.com\/ncert-solutions-for-class-8-maths-chapter-12-ex-12-2\/","title":{"rendered":"NCERT Solutions for Class 8 Maths Chapter 12 Exponents and Powers Ex 12.2"},"content":{"rendered":"

These NCERT Solutions for Class 8 Maths<\/a> Chapter 12 Exponents and Powers Ex 12.1 Questions and Answers are prepared by our highly skilled subject experts.<\/p>\n

NCERT Solutions for Class 8 Maths Chapter 12 Exponents and Powers Exercise 12.2<\/h2>\n

Question 1.
\nExpress the following numbers in standard form.
\n(i) 0.0000000000085
\n(ii) 0.00000000000942
\n(iii) 6020000000000000
\n(iv) 0.00000000837
\n(v) 31860000000
\nAnswer:
\n(i) 0.0000000000085 = \\(\\frac{85}{10^{13}}=\\frac{8.5 \\times 10}{10^{13}}\\)
\n= 8.5 \u00d7 10 \u00d7 10-13<\/sup> = 8.5 \u00d7 10-12<\/sup><\/p>\n

\"NCERT<\/p>\n

(ii) 0.00000000000942 = \\(\\frac{942}{10^{14}}\\)
\n= \\(\\frac{9.42 \\times 100}{10^{14}}=\\frac{9.42 \\times 10^{2}}{10^{14}}\\)
\n= 9.42 \u00d7 102<\/sup> \u00d7 10-14<\/sup> = 9.42 \u00d7 10-12<\/sup><\/p>\n

(iii) 6020000000000000 = 602 \u00d7 1013<\/sup>
\n= 6.02 \u00d7 102<\/sup> \u00d7 1013<\/sup> = 6.02 \u00d7 1015<\/sup><\/p>\n

(iv) 0.00000000837 = \\(\\frac{837}{10^{11}}=\\frac{8.37 \\times 10^{2}}{10^{11}}\\)
\n= 8.37 \u00d7 102 -11<\/sup> = 8.37 \u00d7 10-9<\/sup><\/p>\n

(v) 31860000000 = 3186 \u00d7 107<\/sup>
\n= 3.186 \u00d7 103<\/sup> \u00d7 107<\/sup>
\n= 3.186 \u00d7 103<\/sup> + 103+7<\/sup>
\n= 3.186 \u00d7 1010<\/sup><\/p>\n

Question 2.
\nExpress the following numbers in usual form.
\n(i) 3.02 \u00d7 10-6<\/sup>
\n(ii) 4.5 \u00d7 104<\/sup>
\n(iii)3 \u00d7 10-8<\/sup>
\n(iv) 1.0001 \u00d7 109<\/sup>
\n(v) 5.8 \u00d7 1012<\/sup>
\n(vi) 3.61492 \u00d7 106<\/sup>
\nAnswer:
\n(i) 3.02 \u00d7 10-6<\/sup> = 302 x 10-2<\/sup> \u00d7 10-6<\/sup>
\n= 302 \u00d7 10-8<\/sup> = 0.00000302<\/p>\n

(ii) 4.5 \u00d7 104<\/sup> = \\(\\frac{45}{10}\\) \u00d7 10000 = 45000<\/p>\n

(iii) 3 \u00d7 10-5<\/sup> = \\(\\frac{3}{10^{8}}\\) = 0.00000003<\/p>\n

(iv) 1.0001 \u00d7 109<\/sup> = \\(\\frac{10001 \\times 10^{9}}{10^{4}}\\)
\n= 10001 \u00d7 109-4<\/sup> = 10001 \u00d7 105<\/sup>
\n= 1000100000<\/p>\n

(v) 5.8 \u00d7 1012<\/sup> = \\(\\frac{58}{10}\\) \u00d7 1012<\/sup> = 58 \u00d7 1012-1<\/sup>
\n= 58 \u00d7 1012-1<\/sup> = 58 \u00d7 1011<\/sup>
\n= 5800000000000<\/p>\n

\"NCERT<\/p>\n

(vi) 3.61492 x 106<\/sup> = \\(\\frac{361492}{10^{5}}\\) \u00d7 106<\/sup>
\n= 361492 \u00d7 106-5<\/sup> = 361492 \u00d7 10
\n= 36149200<\/p>\n

Question 3.
\nExpress the number appearing in the following statements in standard form.
\n(i) 1 micron is equal to \\(\\frac{1}{1000000}\\) m.
\n(ii) Charge of an electron is 0.000,000,000,000,000,000,16 coulomb.
\n(iii) Size of a bacteria is 0.0000005 m
\n(iv) Size of a plant cell is 0.00001275 m
\n(v) Thickness of a thick paper is 0.07 mm
\nAnswer:
\n(i) \\(\\frac{1}{1000000}=\\frac{1}{10^{6}}\\) = 1 \u00d7 10-6<\/sup>
\n1 micron = 1 \u00d7 10-6<\/sup><\/p>\n

(ii) 0.000,000,000,000,000,000,16 = \\(\\frac{16}{10^{20}}\\)
\n= \\(\\frac{1.6 \\times 10}{10^{20}}\\) = 1.6 \u00d7 101-20<\/sup> = 1.6 \u00d7 10-19<\/sup>
\n.’. Charge on an electron is 1.6 \u00d7 10-19<\/sup> coulomb.<\/p>\n

(iii) 0.0000005 = \\(\\frac{5}{10^{7}}\\) = 5 \u00d7 10-7<\/sup>
\nSize of a bacteria = 5 \u00d7 10-7<\/sup> m<\/p>\n

(iv) 0.00001275 = \\(\\frac{1275}{10^{8}}=\\frac{1.275 \\times 10^{3}}{10^{8}}\\)
\n= 1.275 \u00d7 103-8<\/sup> = 1.275 \u00d7 10-5<\/sup>
\nSize of a plant cell is 1.275 \u00d7 10-5<\/sup>m<\/p>\n

(v) 0.07 = \\(\\frac{7}{10^{2}}\\) = 7 \u00d7 10-2<\/sup>
\n.’. Thickness of a thick paper is 7 \u00d7 10-2<\/sup>mm<\/p>\n

\"NCERT<\/p>\n

Question 4.
\nIn a stack, there are 5 books each of thickness 20 mm and 5 paper sheets each of thickness 0.016 mm. What is the total thickness of the stack.
\nAnswer:
\nThickness of one book = 20 mm
\nThickness of 5 books = 5 \u00d7 20 mm = 100 mm
\nAgain, Thickness of one paper sheet = 0.016 mm
\n.’. Thickness of 5 paper sheets = 5\u00d7 0.016 mm
\n= 0.080 m
\nTotal thickness =100 mm + 0.080 mm = 100.08 mm
\n\\(\\frac{10008}{10^{2}}=\\frac{1.0008 \\times 10^{4}}{10^{2}}\\)
\n= 1.0008 \u00d7 102<\/sup> mm<\/p>\n","protected":false},"excerpt":{"rendered":"

These NCERT Solutions for Class 8 Maths Chapter 12 Exponents and Powers Ex 12.1 Questions and Answers are prepared by our highly skilled subject experts. NCERT Solutions for Class 8 Maths Chapter 12 Exponents and Powers Exercise 12.2 Question 1. Express the following numbers in standard form. (i) 0.0000000000085 (ii) 0.00000000000942 (iii) 6020000000000000 (iv) 0.00000000837 …<\/p>\n

NCERT Solutions for Class 8 Maths Chapter 12 Exponents and Powers Ex 12.2<\/span> Read More »<\/a><\/p>\n","protected":false},"author":9,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"site-sidebar-layout":"default","site-content-layout":"default","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","theme-transparent-header-meta":"default","adv-header-id-meta":"","stick-header-meta":"default","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","spay_email":""},"categories":[7],"tags":[],"yoast_head":"\nNCERT Solutions for Class 8 Maths Chapter 12 Exponents and Powers Ex 12.2 - MCQ Questions<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/mcq-questions.com\/ncert-solutions-for-class-8-maths-chapter-12-ex-12-2\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"NCERT Solutions for Class 8 Maths Chapter 12 Exponents and Powers Ex 12.2 - MCQ Questions\" \/>\n<meta property=\"og:description\" content=\"These NCERT Solutions for Class 8 Maths Chapter 12 Exponents and Powers Ex 12.1 Questions and Answers are prepared by our highly skilled subject experts. 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