Chapter-2 Power Play — Online MCQ Test
MATHS · Grade 8 · CBSE(NCERT)
Practice Chapter-2 Power Play with a free chapter-wise online MCQ test.
This chapter covers: exponents - base - negative exponents - laws of exponents - scientific notation - standard form.
AI-generated questions from basic to board-exam level, with instant results and explanations.
Chapter-2 Power Play — Important Questions & Answers
What is the base in the expression 5³?
- A. 3
- B. 5
- C. 15
- D. 125
Answer: B. 5
In an exponential expression, the base is the number being multiplied. In 5³, 5 is the base and 3 is the exponent.
In an exponential expression, the base is the number being multiplied. In 5³, 5 is the base and 3 is the exponent.
What does 2⁴ equal?
- A. 8
- B. 16
- C. 32
- D. 6
Answer: B. 16
2⁴ = 2 × 2 × 2 × 2 = 16. The exponent 4 means multiply the base 2 by itself 4 times.
2⁴ = 2 × 2 × 2 × 2 = 16. The exponent 4 means multiply the base 2 by itself 4 times.
Express 10,000 as a power of 10.
- A. 10²
- B. 10³
- C. 10⁴
- D. 10⁵
Answer: C. 10⁴
10⁴ = 10 × 10 × 10 × 10 = 10,000. Four zeros in 10,000 means the exponent is 4.
10⁴ = 10 × 10 × 10 × 10 = 10,000. Four zeros in 10,000 means the exponent is 4.
What is 3⁻²?
- A. -9
- B. 1/9
- C. -1/9
- D. 9
Answer: B. 1/9
A negative exponent means the reciprocal. 3⁻² = 1/3² = 1/9.
A negative exponent means the reciprocal. 3⁻² = 1/3² = 1/9.
Using the law of exponents, simplify: 2³ × 2²
- A. 2⁵
- B. 2⁶
- C. 4⁵
- D. 2¹
Answer: A. 2⁵
When multiplying powers with the same base, add the exponents: 2³ × 2² = 2^(3+2) = 2⁵.
When multiplying powers with the same base, add the exponents: 2³ × 2² = 2^(3+2) = 2⁵.
Simplify: (3²)³
- A. 3⁵
- B. 3⁶
- C. 9³
- D. 27
Answer: B. 3⁶
When raising a power to another power, multiply the exponents: (3²)³ = 3^(2×3) = 3⁶.
When raising a power to another power, multiply the exponents: (3²)³ = 3^(2×3) = 3⁶.
Which expression has the greatest value?
- A. 2⁵
- B. 3⁴
- C. 4³
- D. 5²
Answer: A. 2⁵
2⁵ = 32, 3⁴ = 81, 4³ = 64, 5² = 25. Actually, 3⁴ = 81 is greatest. Let me recalculate: B is correct.
2⁵ = 32, 3⁴ = 81, 4³ = 64, 5² = 25. Actually, 3⁴ = 81 is greatest. Let me recalculate: B is correct.
If 3ˣ × 3⁵ = 3⁸, find x.
- A. 2
- B. 3
- C. 4
- D. 5
Answer: B. 3
Using the law of exponents, 3ˣ × 3⁵ = 3^(x+5) = 3⁸, so x + 5 = 8, therefore x = 3.
Using the law of exponents, 3ˣ × 3⁵ = 3^(x+5) = 3⁸, so x + 5 = 8, therefore x = 3.
Simplify: (10⁻¹ + 10⁻²) × 10³
- A. 110
- B. 1.1 × 10³
- C. 111
- D. 0.11
Answer: A. 110
(10⁻¹ + 10⁻²) = 0.1 + 0.01 = 0.11. Then 0.11 × 10³ = 110.
(10⁻¹ + 10⁻²) = 0.1 + 0.01 = 0.11. Then 0.11 × 10³ = 110.
Which statement is true?
- A. 2³ × 3³ = 6³
- B. 2³ + 3³ = 5³
- C. 2⁻¹ + 3⁻¹ = 5⁻¹
- D. (2 + 3)² = 2² + 3²
Answer: A. 2³ × 3³ = 6³
2³ × 3³ = 8 × 27 = 216, and 6³ = 216. This follows the law (a × b)ⁿ = aⁿ × bⁿ.
2³ × 3³ = 8 × 27 = 216, and 6³ = 216. This follows the law (a × b)ⁿ = aⁿ × bⁿ.