Which of the following energy band diagrams shows the $N-$type semiconductor and $P-$type semiconductor respectively?

The valence of an impurity added to germanium crystal in order to convert it into a $P-$type semiconductor is

Pure $Si$ at $500\,K$ has equal number of electron $(n_e)$ and hole $(n_h)$ concentrations of $1.5 \times 10^{16}\,m^{-3}$. Doping by indium increases $n_h$ to $4.5 \times 10^{22}\,m^{-3}$. The doped semiconductor is of

Which of the following statements is not true?

The number of silicon atoms per $m^3$ is $5 \times 10^{28}$. This is doped with $4.5 \times 10^{21}$ atoms $/ m^3$ of Arsenic. The ratio of the number of electrons to the number of holes after doping is (Take $n_i = 1.5 \times 10^{16} / m^3$)

The number of silicon atoms per $m^{3}$ is $5 \times 10^{28}$. This is doped simultaneously with $5 \times 10^{22}$ atoms per $m^{3}$ of Arsenic and $5 \times 10^{20}$ atoms per $m^{3}$ of Indium. Calculate the number of electrons and holes. Given that $n_{i} = 1.5 \times 10^{16} \; m^{-3}$. Is the material $n$-type or $p$-type?