In a $p-n-p$ transistor, the current carriers are

In an $n-p-n$ transistor,

$A$ common emitter amplifier has a voltage gain of $50$,an input impedance of $100\; \Omega$,and an output impedance of $200\; \Omega$. The power gain of the amplifier is:

The transistors provide good power amplification when they are used in

$A$ change of $0.04 \ V$ takes place between the base and the emitter when an input signal is connected to the common emitter transistor amplifier. As a result,a $20 \ \mu A$ change takes place in the base current and a change of $2 \ mA$ takes place in the collector current. The input resistance and $AC$ current gain are:

$10^{10}$ electrons enter the emitter of a junction transistor in a time of $0.4 \mu s$. If $5 \%$ of the electrons are lost in the base, then the collector current is (in $\text{ mA}$)