Q 12-14-181JEE MainJEE Main 2019 (9 Jan, Shift 1)Easy
Mobility of electrons in a semiconductor is defined as the ratio of their drift velocity to the applied electric field. If, for an N-type semiconductor, the density of electrons is $10^{19}\ \text{m}^{-3}$ and their mobility is $1.6\ \text{m}^2\text{V}^{-1}\text{s}^{-1}$, then the resistivity of the semiconductor (since it is an N-type semiconductor contribution of holes is ignored) is close to
Answer: (D) $0.4\ \Omega\,\text{m}$
Conductivity from electrons only: $\sigma = ne\mu$.
$$\rho = \frac{1}{ne\mu} = \frac{1}{10^{19}\times1.6\times10^{-19}\times1.6} = \frac{1}{2.56} \approx 0.4\ \Omega\,\text{m}$$
Solution by Sreeraj P, M.Sc Physics