Current Electricity Charging Discharging Of Capacitors Question 359

Question: 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 $ l $ and area of cross-section $ A $ will be

[CPMT 1992]

Options:

A) $ \frac{ml}{ne^{2}\tau A} $

B) $ \frac{m{{\tau }^{2}}A}{ne^{2}l} $

C) $ \frac{ne^{2}\tau A}{2ml} $

D) $ \frac{ne^{2}A}{2m\tau l} $

Show Answer

Answer:

Correct Answer: A

Solution:

$ R=\rho \frac{l}{A}=\frac{n}{ne^{2}\tau }.\frac{l}{A} $