$A$ $N-$ type semiconductor is

$A$ pure silicon crystal at temperature $300 \text{ K}$ has electron and hole concentration $(n_i) = 10^{16} \text{ per m}^3$ each. If $10^{21}$ phosphorus atoms $(n_D)$ are added per cubic metre, what is the new hole concentration in the silicon crystal?

What is the conductivity of a pure silicon crystal at $300 \ K$? The number of electron-hole pairs per $cm^3$ is $1.072 \times 10^{10}$. Given $\mu_n = 1350 \ cm^2/V \cdot s$ and $\mu_p = 480 \ cm^2/V \cdot s$.

If the ratio of electron and hole currents in a semiconductor is $\frac{7}{4}$ and the ratio of drift velocities of electrons and holes is $\frac{5}{4}$, then the ratio of concentrations of electrons and holes will be

In an $N$-type semiconductor,where are the donor energy levels $E_D$ located?

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