By increasing the temperature, the specific resistance of a conductor and a semiconductor respectively

Which of the following statements is TRUE for n-type semiconductor?

In a common emitter transistor amplifier circuit, the current gain $\alpha=0.8$. If the base current changes by $3 \mu \mathrm{~A}$ then the collector current changes by

In the case of common emitter transistor amplifier, the ratio of collector current to emitter current is 0.96 , then the current gain $(\beta)$ of the amplifier is