If ${n_e}$ and ${n_h}$ are the number of electrons and holes in a semiconductor heavily doped with phosphorus,then

$A$ semiconductor doped with a donor impurity is

In an $n$-type semiconductor,the free electrons donated by the impurity atoms occupy energy levels in:

An intrinsic semiconductor is electrically neutral. An extrinsic semiconductor having a large number of current carriers would be:

$A$ 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:

$A$ $P$-type semiconductor is .......