In $p-$type semiconductor,the majority charge carriers are

The valence of the impurity atom that is to be added to a germanium crystal to make it an $N$-type semiconductor is:

In a sample of pure silicon, $10^{13} \text{ atoms/cm}^3$ of phosphorus is added. If all donor atoms are active and the electron mobility is $1200 \text{ cm}^2/\text{V}\cdot\text{s}$, what will be the resistivity at $20^\circ\text{C}$ in $\Omega\cdot\text{cm}$?

$A$ 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 $,A$)

When a small amount of impurity atoms are added to a semiconductor, then generally its resistivity:

In $n$-type semiconductor,which of the following statements is true?