Silicon is a semiconductor. If a small amount of $As$ is added to it,then its electrical conductivity . . . . . . .

In Germanium,the concentration of Aluminum is $\sim 10^{21} \text{ atoms}/m^3$. The intrinsic carrier concentration in the pure semiconductor is $\sim 10^{19} /m^3$. After adding the impurity,what is the electron concentration?

Mobilities of electrons and holes in a sample of intrinsic $Ge$ at room temperature are $0.35 \, m^2/V-s$ and $0.18 \, m^2/V-s$ respectively. If the electron and hole densities are each equal to $2.5 \times 10^{19} \, /m^3$,the $Ge$ conductivity will be.....$S/m$ (in $.12$)

Electric conduction in a semiconductor takes place due to

At room temperature,a $p$-type semiconductor has

Which of the following statements is true for an $N$-type semiconductor?