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

In $n$-type semiconductor,electrons are majority charge carriers,but it does not show any negative charge. The reason is:

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

Pure silicon at $300 \ K$ has equal electron and hole concentration of $1.5 \times 10^{16} \ m^{-3}$. If the hole concentration increases to $3 \times 10^{22} \ m^{-3}$,then the electron concentration in the silicon is

What is the relation between the number density of holes $(n_h)$ and free electrons $(n_e)$ in an intrinsic semiconductor at room temperature?

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