In a $P-$type semiconductor,germanium is doped with

$A$ pure semiconductor has equal electron and hole concentration of $10^{16} \ m^{-3}$. Doping by gallium increases $n_{h}$ to $5 \times 10^{22} \ m^{-3}$. Then,the value of $n_{e}$ in the doped semiconductor is

If a semiconductor has an intrinsic carrier concentration of $1.41 \times 10^{16} \, m^{-3}$,when doped with $10^{21} \, m^{-3}$ phosphorus,then the concentration of holes at room temperature will be

The length of a germanium rod is $0.928 \ cm$ and its area of cross-section is $1 \ mm^2$. If for germanium $n_i = 2.5 \times 10^{19} \ m^{-3}$,$\mu_h = 0.15 \ m^2 V^{-1} s^{-1}$,and $\mu_e = 0.35 \ m^2 V^{-1} s^{-1}$,then the resistivity is:

Indium impurity in germanium makes

The contribution in the total current flowing through a semiconductor due to electrons and holes are $\frac{3}{4}$ and $\frac{1}{4}$ respectively. If the drift velocity of electrons is $\frac{5}{2}$ times that of holes at this temperature,then the ratio of concentration of electrons and holes is