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 semiconuctor, the density of electrons is `10^(19)m^(-3)` and their mobility is `1.6m^(2)//(V.s)` then the resistivity of the semiconductor (since it is an n-type semiconductor contribution of holes is ignored) is close to :

Options

A. `2Omegam`
B. `4Omegam`
C. `0.2Omegam`
D. `0.4Omegam`

Answer

D

Explanation

If contribution of holes is neglected then
`I= n e Av_(e)=n eAmu_(e)Eimplies(VA)/(rho l)=n eA mu_(e)E`
`impliesrho=1/(n e mu_(e))=1/(10^(19)xx1.6xx10^(-19)xx1.6)=100/((16)^(2))=0.39Omega-m~~0.4Omegam`