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Question: Answered & Verified by Expert
A uniform wire of resistance $R$ is uniformly compressed along its length, until its radius becomes $n$ times the original radius. Now resistance of the wire becomes
PhysicsCurrent ElectricityJEE Main
Options:
  • A $\frac{R}{n^4}$
  • B $\frac{R}{n^2}$
  • C $\frac{R}{n}$
  • D $n R$
Solution:
2632 Upvotes Verified Answer
The correct answer is: $\frac{R}{n^4}$
$\frac{R_1}{R_2}=\left(\frac{r_2}{r_1}\right)^4 \Rightarrow \frac{R}{R_2}=\left(\frac{n r}{r}\right)^4 \Rightarrow R_2=\frac{R}{n^4}$.

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