If ${l_1}, {l_2}, {l_3}$ are the lengths of the emitter,base,and collector of a transistor,respectively,then:

In an $NPN$ transistor,if the doping in the base region is increased,then the collector current:

For a transistor amplifier,the power gain and voltage gain are $7.5$ and $2.5$ respectively. The value of the current gain will be:

In a common emitter transistor amplifier circuit,the current gain $\alpha = 0.8$. If the base current changes by $3 \mu A$,then the collector current changes by: (in $\mu A$)

An $n-p-n$ transistor is connected in common-emitter configuration as shown in the figure. If the collector current is $5 \text{ mA}$,$V_{BE} = 0.6 \text{ V}$,$V_{CE} = 3 \text{ V}$,and the common-emitter current amplification factor $\beta = 50$,then the values of $R_1$ and $R_2$ are respectively.

For a transistor,$\beta = 100$. The value of $\alpha$ is