Extra Questions: Class 8 Maths Chapter 2 Power Play

Practice questions beyond the textbook exercises, testing deeper understanding of exponent laws and scientific notation for Class 8 Maths Chapter 2: Power Play. These Class 8 Mathematics Chapter 2 important questions are handy for last-minute exam practice.

Extra Questions: Class 8 Maths Chapter 2 Power Play

1. 1 (Assertion-Reason). Assertion: 5⁰ = 1. Reason: Any non-zero number raised to the power zero equals 1.
   Solution: Both true, and the reason correctly explains the assertion — this follows from aⁿ÷aⁿ=a⁰=1 for any a≠0.
2. 2 (Numerical). Simplify: (2³×2⁻&sup5;)÷2⁻&sup4;.
   Solution: 2³×2⁻&sup5; = 2⁻²; then 2⁻²÷2⁻⁴ = 2² = 4.
3. 3 (Numerical). Write 45,00,000 and 0.0000063 in standard (scientific) form.
   Solution: 45,00,000 = 4.5×10⁶; 0.0000063 = 6.3×10⁻⁶.
4. 4 (Applied). Light travels at 3×10⁸ m/s. How far does it travel in 10² seconds? Express in scientific notation.
   Solution: 3×10⁸×10² = 3×10¹⁰ m.
5. 5 (Assertion-Reason). Assertion: (−3)⁴ is positive. Reason: A negative number raised to an even power is always positive.
   Solution: Both true, and the reason correctly explains the assertion: (−3)⁴ = 81, positive, since the exponent 4 is even.
6. 6 (Synthesis). Is 5ⁿ ever equal to 3ⁿ for a positive integer n > 0? Explain.
   Solution: No — since 5 and 3 are different prime bases, 5ⁿ and 3ⁿ can never be equal for any positive integer n (their prime factorisations never match).
7. 7 (Numerical). Simplify: (2⁵)² ÷ (2²)³.
   Solution: (2⁵)²=2¹⁰; (2²)³=2⁶; 2¹⁰÷2⁶= 2⁴ = 16.
8. 8 (Applied). A bacteria culture doubles every hour, starting from 1 bacterium. Write the population after 12 hours as a power of 2, and find its value.
   Solution: After 12 hours: 2¹² = 4096 bacteria.
9. 9 (Assertion-Reason). Assertion: 10⁻³ is smaller than 10⁻². Reason: For powers of 10, a more negative exponent gives a smaller value.
   Solution: Both true and the reason correctly explains it: 10⁻³=0.001 < 10⁻²=0.01.
10. 10 (Numerical). Which is greater: 6³ or 3⁶?
    Solution: 6³=216; 3⁶=729. 3⁶ is greater.

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