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JEE Main 2022 (26 Jun, Shift 1) · Ohm's Law, Resistivity & Temperature

Ohm's Law, Resistivity & Temperature question from JEE Main 2022 (26 Jun, Shift 1)

Q26JEE Main 2022 · 26 JUN · SHIFT 1Easy

Ohm's Law, Resistivity & Temperature

An aluminium wire is stretched to make its length, 0.4% larger. The percentage change in resistance is:

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Answer: (c)

  1. At constant volume R∝l2R \propto l^2, so for small changes ΔRR=2Δll\dfrac{\Delta R}{R} = 2\dfrac{\Delta l}{l}.
  2. ΔRR=2×0.4%=0.8%\dfrac{\Delta R}{R} = 2 \times 0.4\% = 0.8\%
  3. So the answer is (c) 0.8%0.8\%.
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