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Question: Answered & Verified by Expert
If $n, e, \tau$ and $m$ respectively represent the density, charge relaxation time and mass of the electron, then the resistance of a wire of length $I$ and area of cross-section $A$ will be
PhysicsCurrent ElectricityJEE Main
Options:
  • A $\frac{m l}{n e^2 \tau A}$
  • B $\frac{m \tau^2 A}{n e^2 l}$
  • C $\frac{n e^2 \tau A}{2 m l}$
  • D $\frac{n e^2 A}{2 m \pi}$
Solution:
2142 Upvotes Verified Answer
The correct answer is: $\frac{m l}{n e^2 \tau A}$
$R=\rho \frac{I}{A}=\frac{n}{n e^2 \tau} \cdot \frac{I}{A}$

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