The conductivity of a pure semiconductor can be increased by

How is electric conduction produced in an intrinsic semiconductor?

Mobility of electrons in a semiconductor is defined as the ratio of their drift velocity to the applied electric field. If,for an $n$-type semiconductor,the density of electrons is $10^{19} \ m^{-3}$ and their mobility is $1.6 \ m^2/(V \cdot s)$,then the resistivity of the semiconductor (since it is an $n$-type semiconductor,the contribution of holes is ignored) is close to ................ $\Omega \cdot m$.

In an $n$-type semiconductor:

Which of the following statements is incorrect?

When a battery is connected to a $P$-type semiconductor with a metallic wire,the current in the semiconductor (predominantly),inside the metallic wire,and inside the battery is due to which charge carriers respectively?