Question

If $n,e,\tau$ and $m$ are representing electron density, charge, relaxation time and mass of an electron respectively, then the resistance of a wire of length $l$ and cross-sectional area $A$ is given by

• A. $\frac{ml}{n{e}^2\tau A}$
• B. $\frac{m\tau A}{n{e}^{2}l}$
• C. $\frac{n{e}^2\tau A}{ml}$
• D. $\frac{n{e}^{2}A}{m\tau l}$

Answer 1

Answer: (A)

$R=\frac{PI}{A}$
$R=\frac{ml}{n{e}^{2}lA}$