In an $n-p-n$ transistor, the collector current is $28 \,mA$. If $80 \%$ of electrons reach the collector, its base current in $mA$ is

Which one of the operations of $n-p-n$ transistor differs from that of $p-n-p$ transistor?

The voltage gain and the current amplification factor of a transistor in common emitter configuration are $300$ and $60$ respectively. If the collector resistance is $5 \, k\Omega$, then the base resistance is:

In a junction transistor,the collector current changes by $6.8 \,mA$,if the emitter current is changed by $7 \,mA$. For such a transistor,the current amplification factor is

The current amplification factor of a transistor is $50$. The input resistance when used in common emitter mode is $1 \text{ k}\Omega$. The peak value of the collector current for an a.c. input voltage of $0.01 \text{ V}$ peak is:

$A$ transistor is used as a common emitter amplifier with a load resistance $2 \ k\Omega$. The input resistance is $150 \ \Omega$. The base current is changed by $20 \ \mu A$,which results in a change in collector current by $1.5 \ mA$. The voltage gain of the amplifier is