Question

A Silicon sample $A$ is doped with ${10}^{18}atoms/c{m}^3$ of Boron. Another sample $B$ of identical dimensions is doped with ${10}^{18}atoms/c{m}^3$ of Phosphorus. The ratio of electron to hole mobility is $3$. The ratio of conductivity of the sample $A$ to $B$ is

• A. $3$
• B. $3/2$
• C. $1/3$
• D. $2/3$

Answer 1

The correct option is C $1/3$

Ans : (b)

${\sigma }_n=nq{\mu }_n$
${\sigma }_p=pq{\mu }_p$
$\frac{{\sigma }_p}{{\sigma }_n}=\frac{{\mu }_p}{{\mu }_n}=\frac{1}{3}$