The process of adding impurities to a pure semiconductor is called

Which one of the following statements is true? $A$ p-type semiconductor is doped with

The conductivity of a pure semiconductor can be increased by

In a semiconductor,the ratio of the number of electrons to the number of holes is $7/5$ and the ratio of their currents is $7/4$. What is the ratio of their drift velocities?

In a $P$-type semiconductor, the acceptor energy level $E_A$ is located $57 \, meV$ above the valence band. The maximum wavelength required to create a hole is ....... $\mathring{A}$. (Given: $h = 6.6 \times 10^{-34} \, J \, s$, $c = 3 \times 10^8 \, m/s$, $1 \, eV = 1.6 \times 10^{-19} \, J$)

Germanium $(Ge)$ is doped with Aluminum $(Al)$. If the concentration of acceptor atoms is $N_A \cong 10^{21} \text{ atoms/m}^3$ and the intrinsic carrier concentration is $n_i = 10^{19} \text{ m}^{-3}$,then the concentration of electrons is: