Which of these is a unipolar transistor?

In an $NPN$ transistor,$10^{10}$ electrons enter the emitter in $10^{-6} \ s$ and $2 \%$ of electrons recombine with holes in the base. The current ratios $\alpha$ and $\beta$ of the transistor are respectively (nearly):

While a collector to emitter voltage is constant in a transistor,the collector current changes by $8.2 \, mA$ when the emitter current changes by $8.3 \, mA$. The value of forward current gain $h_{fe}$ is

What is the power gain in a $CE$ amplifier,where input resistance is $3 \, k\Omega$ and load resistance is $24 \, k\Omega$,given $\beta = 6$?

In a common emitter transistor amplifier,the output voltage and input voltage have a phase difference of

In the circuit shown, the value of $\beta$ of the transistor is $48$. If the base current supplied is $200 \mu A$, what is the voltage at the terminal $Y$ (in $V$)?