Laws of Exponents - Class 8 Maths MCQ

This set of Class 8 Maths Chapter 12 Multiple Choice Questions & Answers (MCQs) focuses on “Laws of Exponents”.

1. Find the value of \(\frac{1}{8^{-2}}\).
a) \(\frac{1}{16}\)
b) \(\frac{1}{64}\)
c) 16
d) 64
View Answer

Answer: d
Explanation: \(\frac{1}{a^{-m}}\) = a^m
⇒ \(\frac{1}{8^{-2}}\) = 8² = 64.

2. What is 2^-3?
a) \(\frac{1}{4}\)
b) \(\frac{1}{8}\)
c) 4
d) 8
View Answer

Answer: b
Explanation: a^-m = \(\frac{1}{a^m}\)
⇒ 2^-3 = \(\frac{1}{2^3}\) = \(\frac{1}{8}\).

3. Find the value of 16^-2 × 16¹⁴.
a) 16¹²
b) 16^-12
c) 16¹⁴
d) 16^-14
View Answer

Answer: a
Explanation: a^m × aⁿ = a^{m + n}
⇒ 16^-2 × 16¹⁴ = 16^{-2 + 14} = 16¹².

4. Evaluate \((\frac{21^{29}}{21^5})\).
a) 21²⁵
b) 21^-25
c) 21²⁴
d) 21^-24
View Answer

Answer: c
Explanation: \(\frac{a^m}{a^n}\) = a^{m – n}
⇒ \((\frac{21^{29}}{21^5})\) = 21^{29 – 5} = 21²⁴.

5. Match the pairs.

A	B
1) 2³ × 8³	a. 1
2) \(\frac{8^3}{2^3}\)	b. 16³
3) (2³)⁰	c. 4³
	d. 8

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a) 1-b, 2-c, 3-d
b) 1-b, 2-c, 3-a
c) 1-c, 2-b, 3-a
d) 1-c, 2-b, 3-d
View Answer

Answer: b
Explanation: a^m × b^m = (ab)^m
⇒ 2³ × 8³ = (2 × 8)³ = 16³
Now, \(\frac{a^m}{b^m} = (\frac{a}{b})^m\)
⇒ (\(\frac{8}{2})^3\) = 4³
Also, (a^m)ⁿ = a^mn, a⁰ = 1
⇒ (2³)⁰ = 2^{3 × 0} = 2⁰ = 1.

6. Find the value of (2³)².
a) 128
b) 16
c) 32
d) 64
View Answer

Answer: d
Explanation: (a^m)ⁿ = a^mn
⇒ (2³)² = 2⁶ = 64.

Sanfoundry Global Education & Learning Series – Mathematics – Class 8.

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