If the ratio of electron and hole currents in a semiconductor is $\frac{7}{4}$ and the ratio of drift velocities of electrons and holes is $\frac{5}{4}$, then the ratio of concentrations of electrons and holes will be

$A$ hole in a $P-$type semiconductor is

$A$ $P-$ type semiconductor can be obtained by adding

When an impurity is doped into an intrinsic semiconductor,the conductivity of the semiconductor

If $n_e$ and $n_h$ are electron and hole concentrations in an extrinsic semiconductor and $n_i$ is the intrinsic carrier concentration, then:

$A$ silicon specimen is made into a $p$-type semiconductor by doping,on an average,one indium atom per $5 \times 10^7$ silicon atoms. If the number density of atoms in the silicon specimen is $5 \times 10^{28} \text{ atoms } m^{-3}$,then the number of acceptor atoms in silicon per cubic centimeter will be: