Class 8 Maths Chapter 12 Exponents and Powers All Exercise NCERT Solutions

Class 8 Maths Chapter 12 Exponents and Powers All Exercise NCERT Solutions

• Class 8 Maths Exponents and Powers Exercise 12.1
• Class 8 Maths Exponents and Powers Exercise 12.2

NCERT Solutions for Class 8 Maths Chapter 12 Exponents and Powers Exercise 12.1

Ex 12.1 Class 8 Maths Question 1.
Evaluate:
(i) 3-2
(ii) (-4)-2
(iii) (12)-5
Solution:

Ex 12.1 Class 8 Maths Question 2.
Simplify and express the result in power notation with a positive exponent.

Solution:

Ex 12.1 Class 8 Maths Question 3.
Find the value of

Solution:

Ex 12.1 Class 8 Maths Question 4.

Solution:

Ex 12.1 Class 8 Maths Question 5.
Find the value of m for which 5m ÷ 5-3 = 55.
Solution:
5m ÷ 5-3 = 55
⇒ 5m-(-3) = 55 [∵ am ÷ an = am-n]
⇒ 5m+3 = 55
Comparing the powers of equal bases, we have
m + 3 = 5
m = 5 – 3 = 2, i.e., m = 2

Ex 12.1 Class 8 Maths Question 6.
Evaluate:

Solution:

Ex 12.1 Class 8 Maths Question 7.
Simplify:

Solution:

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

Ex 12.2 Class 8 Maths Question 1.
Express the following numbers in standard form:
(i) 0.0000000000085
(ii) 0.00000000000942
(iii) 6020000000000000
(iv) 0.00000000837
(v) 31860000000
Solution:

(v) 31860000000
= 3.186 × 10000000000
= 3.186 × 1010
Hence, the required standard from = 3.186 × 1010

Ex 12.2 Class 8 Maths 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
Solution:

Ex 12.2 Class 8 Maths Question 3.
Express the number appearing in the following statements in standard form.
(i) 1 micron is equal to 11000000 m.
(ii) Charge of an electron is 0.000,000,000,000,000,000,16 coulomb
(iii) Size of a bacteria is 0.0000005 m
(iv) Size of a plant cell is 0.00001275 m
(v) Thickness of a thick paper is 0.07 mm.
Solution:

Ex 12.2 Class 8 Maths 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?
Solution:
Thickness of books = 5 × 20 = 100 mm
Thickness of 5 paper sheets = 5 × 0.016 mm = 0.080 mm.
Total thickness of the stack = 100 mm + 0.080 mm = 100.080 mm = 1.0008 × 102 mm

NCERT Solutions for Class 8 Maths

• Chapter 1 Rational Numbers
• Chapter 2 Linear Equations in One Variable
• Chapter 3 Understanding Quadrilaterals
• Chapter 4 Practical Geometry
• Chapter 5 Data Handling
• Chapter 6 Squares and Square Roots
• Chapter 7 Cubes and Cube Roots
• Chapter 8 Comparing Quantities
• Chapter 9 Algebraic Expressions and Identities
• Chapter 10 Visualising Solid Shapes
• Chapter 11 Mensuration
• Chapter 12 Exponents and Powers
• Chapter 13 Direct and Indirect proportions
• Chapter 14 Factorisation
• Chapter 15 Introduction to Graphs
• Chapter 16 Playing with Numbers