If the length of a wire is stretched to double its original length while keeping its volume constant, its new resistance will be: MCQ with Answer and Explanation
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Question #1
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A boy throws a ball vertically upward with velocity 20 m/s. Time after which ball returns to his hands (g=10) is
Question #2
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Three resistors of 2Ω, 3Ω, and 6Ω are connected in parallel. The equivalent resistance is:
Correct Answer: Option A
Explanation:
For parallel combination: 1/R_eq = 1/R₁ + 1/R₂ + 1/R₃ = 1/2 + 1/3 + 1/6 = (3+2+1)/6 = 6/6 = 1. Thus R_eq = 1Ω. Note: Equivalent resistance in parallel is always less than the smallest individual resistance (here 2Ω). Memory tip: 'Parallel: reciprocal sum; result < min(R)'. This standard calculation tests parallel resistance formula application, frequently appearing in competitive exams. Always simplify fractions carefully; common denominator method avoids errors. Verify: 1Ω < 2Ω, consistent with parallel behavior.
For parallel combination: 1/R_eq = 1/R₁ + 1/R₂ + 1/R₃ = 1/2 + 1/3 + 1/6 = (3+2+1)/6 = 6/6 = 1. Thus R_eq = 1Ω. Note: Equivalent resistance in parallel is always less than the smallest individual resistance (here 2Ω). Memory tip: 'Parallel: reciprocal sum; result < min(R)'. This standard calculation tests parallel resistance formula application, frequently appearing in competitive exams. Always simplify fractions carefully; common denominator method avoids errors. Verify: 1Ω < 2Ω, consistent with parallel behavior.
Question #3
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Beats used for:
Correct Answer: Option A
Explanation:
Beats: tune instruments (zero beat = matched frequency); measure sound speed via known frequency difference. Memory tip: 'Beats: tuning and measurement applications'. Wave phenomenon application frequently tested in competitive exams.
Beats: tune instruments (zero beat = matched frequency); measure sound speed via known frequency difference. Memory tip: 'Beats: tuning and measurement applications'. Wave phenomenon application frequently tested in competitive exams.
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