Which of the following statements is correct regarding the charge of semiconductors?

The addition of antimony atoms to a sample of intrinsic germanium transforms it into a material which is:

To obtain electrons as majority charge carriers in a semiconductor,the impurity mixed is

$A$ potential difference of $2\,V$ is applied between the opposite faces of a $Ge$ crystal plate of area $1\,cm^{2}$ and thickness $0.5\,mm$. If the concentration of electrons in $Ge$ is $2 \times 10^{19}/m^{3}$ and mobilities of electrons and holes are $0.36\,m^{2}/(V\cdot s)$ and $0.14\,m^{2}/(V\cdot s)$ respectively,then the current flowing through the plate will be... (in $,A$)

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

Which of the following statements is $\underline{TRUE}$ for $n$-type semiconductor?