$A$ semiconductor is doped with phosphorous atoms as an impurity. The impurity levels created in the semiconductor are close to the

If $N_A$ is the number density of acceptor atoms added and $N_D$ is the number density of donor atoms added to a semiconductor,and $n_e$ and $n_h$ are the number density of electrons and holes in it,then:

Suppose a pure $Si$ crystal has $5 \times 10^{28}$ atoms $m^{-3}$. It is doped with $1 \text{ ppm}$ concentration of pentavalent $As$. Calculate the number of electrons and holes. $(n_i = 1.5 \times 10^{16} \text{ m}^{-3})$

$A$ semiconductor doped with a donor impurity is

In a $p$-type semiconductor,

Statement-$I$: By doping silicon semiconductor with pentavalent material,the electron density increases.
Statement-$II$: The $n$-type semiconductor has a net negative charge.
In the light of the above statements,choose the most appropriate answer from the options given below: