The net charge on an $N-$type semiconductor is

The Bohr radius of the fifth electron of phosphorus (atomic number $Z = 15$) acting as a dopant in silicon (relative dielectric constant $\varepsilon_r = 12$) is ....... $\mathring{A}$.

In a pure silicon $(n_i = 10^{16}/m^3)$ crystal at $300\, K$,$10^{21}$ atoms of phosphorus are added per cubic meter. The new hole concentration will be

$A$ semiconductor has equal electron and hole concentration of $6 \times 10^8 \, m^{-3}$. On doping with a certain impurity,the electron concentration increases to $9 \times 10^{12} \, m^{-3}$. The new hole concentration is:

In an $n$-type semiconductor,the free electrons donated by the impurity atoms occupy energy levels in:

Which of the following statements is correct for an $n$-type semiconductor?