In a transistor, comparing the doping of emitter, base, and collector, the part which is heavily doped and that which is lightly doped are respectively:

$A$ transistor works as an amplifier when

The input voltage applied to a $CE$ amplifier is $v_i = 0.2 \sin(1000t) \text{ V}$. If the voltage gain of the amplifier is $10$,the equation for the output voltage is ....... $\text{V}$.

In a transistor amplifier,the base-emitter junction is forward-biased and the collector-emitter junction is reverse-biased. The current gain is defined as:

$A$ common emitter transistor amplifier is connected with a load resistance of $6 k\Omega$. When a small a.c. signal of $15 mV$ is added to the base-emitter voltage, the alternating base current is $20 \mu A$ and the alternating collector current is $1.8 mA$. What is the voltage gain of the amplifier?

The current gain for a transistor working as a common base amplifier is $0.96$. If the emitter current is $7.2 \,mA$, then the base current is (in $\,mA$)