The NCERT exercise question and answers given here help students frame perfect solutions in Maths. The solutions are provided with the aim of helping students in mastering the concepts by practising the problems. Class 8 NCERT Solutions Mathematics Chapter 12, Exponents and Powers, is a set of questions and answers for all the exercises prepared by BYJU’S Maths subject experts. Download NCERT Solutions for Maths Chapter 12 and strengthen your basics.
NCERT Solutions for class 8 Maths Chapter 12 Exponents and Powers Exercise 12.2
Access Another Exercise Solutions of Class 8 Maths Chapter 12 Exponents and Powers
Exercise 12.1 Solutions: 7 Questions (Short answers)
Access Answers to NCERT Class 8 Chapter 12 Exponents and Powers Exercise 12.2 Page number 200
1. Express the following numbers in standard form.
(i) 0.0000000000085
(ii) 0.00000000000942
(iii) 6020000000000000
(iv) 0.00000000837
(v) 31860000000
Solution:
(i) 0.0000000000085 = 0.0000000000085×(1012/1012) = 8.5 ×10-12
(ii) 0.00000000000942 = 0.00000000000942×(1012/1012) = 9.42×10-12
(iii) 6020000000000000 = 6020000000000000×(1015/1015) = 6.02×1015
(iv) 0.00000000837 = 0.00000000837×(109/109) = 8.37×10-9
(v) 31860000000 = 31860000000×(1010/1010) = 3.186×1010
2. Express the following numbers in the usual form.
(i) 3.02×10-6
(ii) 4.5×104
(iii)3×10-8
(iv)1.0001×109
(v) 5.8×1012
(vi)3.61492×106
Solution:
(i) 3.02×10-6 = 3.02/106 = 0 .00000302
(ii) 4.5×104 = 4.5×10000 = 45000
(iii) 3×10-8 = 3/108 = 0.00000003
(iv) 1.0001×109 = 1000100000
(v) 5.8×1012 = 5.8×1000000000000 = 5800000000000
(vi) 3.61492×106 = 3.61492×1000000 = 3614920
3. Express the number appearing in the following statements in standard form.
(i) 1 micron is equal to 1/1000000 m.
(ii) Charge of an electron is 0.000, 000, 000, 000, 000, 000, 16 coulomb.
(iii) Size of bacteria is 0.0000005 m
(iv) Â Size of a plant cell is 0.00001275 m
(v) Thickness of a thick paper is 0.07 mm
Solution :
(i) 1 micron = 1/1000000
= 1/106
= 1×10-6
(ii) Charge of an electron is 0.00000000000000000016 coulomb.
= 0.00000000000000000016×1019/1019
= 1.6×10-19 coulomb
(iii)Â Size of bacteria = 0.0000005
= 5/10000000 = 5/107 = 5×10-7 m
(iv) Size of a plant cell is 0.00001275 m
= 0.00001275×105/105
= 1.275×10-5m
(v)Â Thickness of a thick paper = 0.07 mm
0.07 mm = 7/100 mm = 7/102 = 7×10-2 mm
4. In 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?
Solution:
Thickness of one book = 20 mm
Thickness of 5 books = 20×5 = 100 mm
Thickness of one paper = 0.016 mm
Thickness of 5 papers = 0.016×5 = 0.08 mm
Total thickness of a stack = 100+0.08 = 100.08 mm
= 100.08×102/102 mm
mm
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NCERT Solutions for Class 8 Maths Chapter 12
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