The thinnest part of a transistor is . . . . . .

In case of a bipolar transistor,$\beta = 45$. The potential drop across the collector resistance of $1 \ k\Omega$ is $5 \ V$. The base current is approximately: (in $\mu A$)

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

In an $n-p-n$ transistor amplifier,the collector current is $9 \ mA$. If $90 \%$ of the electrons emitted reach the collector,then

Identify the terminals of this $BJT$ and the type of $BJT$ $(NPN$ or $PNP)$. The multimeter is set to diode test mode (indicated by the symbol),and the black probe is connected to the $COM$ port while the red probe is connected to the $V\Omega$ port. Based on the connections shown in the image,determine the terminal configuration (from left to right) and the transistor type.

In which of the configurations of a transistor, the power gain is highest?