An intrinsic semiconductor has `10^8 m^-3` free electrons and is doped with pentavalent impurity atoms of density `10^24 m^-3`. The free electron density will increase by ........ orders of magnitude.

Options

A. `10^8m^(-3)`
B. `10^(16)m^(-3)`
C. `10^(20)m^(-3)`
D. `10^(24)m^(-3)`

Answer

D

Explanation

Pentavalent impurity atom contributes 1 electron to the intrinsic semiconductor , hence `10^(24)` impurity atom per unit volume will contribute `10^(24)` electrons to the intrinsic semiconductor .
The electron density will increase by `10^(24) m^(-3)`.