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

When a transistor is used as an amplifier in common emitter configuration,which of the following statements are correct?
$(1)$ The base-emitter junction is forward-biased.
$(2)$ The base-emitter junction is reverse-biased.
$(3)$ The input signal is connected in series with the biasing voltage to the base-emitter junction.
$(4)$ The input signal is connected in series with the biasing voltage to the base-collector junction.

Three amplifiers,each having a voltage gain of $10$,are connected in series. The resultant gain would be

In the following common emitter circuit, if $\beta=100$, $V_{CE}=7 \, V$, $V_{BE}$ is negligible, and $R_C=2 \, k\Omega$, then $I_B=$ (in $\, mA$)?

The output characteristics of an $n-p-n$ transistor represent,($I_C =$ collector current,$V_{CE} =$ potential difference between collector and emitter,$I_B =$ base current,$V_{BB} =$ voltage given to base,$V_{BE} =$ the potential difference between base and emitter)

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