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

$1.41 × 10^{16}$

Phosphorus is pentavalent impurity. Its doping will not effect the concentration of holes. So number of holes will be equal to same as in intrinsic semiconductor. So $n_h= 1.41 × 10^{16} m^{–3}$