NCERT Solutions for Class 8 Maths Chapter 12 Exponents and Powers Ex 12.2

NCERT Solutions for Class 8 Maths Chapter 12 Exponents and Powers Ex 12.2

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
(v) 31860000000
Answer:

(v) 31860000000 = 3186 × 10⁷
= 3.186 × 10³ × 10⁷
= 3.186 × 10³ + 10³⁺⁷
= 3.186 × 10¹⁰

Question 2.
Express the following numbers in 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
Answer:
(i) 3.02 × 10^-6 = 302 x 10^-2 × 10^-6
= 302 × 10^-8 = 0.00000302

Question 3.
Express the number appearing in the following statements in standard form.

Question 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.
Answer:
Thickness of one book = 20 mm
Thickness of 5 books = 5 × 20 mm = 100 mm
Again, Thickness of one paper sheet = 0.016 mm
.’. Thickness of 5 paper sheets = 5× 0.016 mm
= 0.080 m
Total thickness =100 mm + 0.080 mm = 100.08 mm

= 1.0008 × 10² mm