In a transistor,when the emitter current changes by $9.85 \,mA$,the collector current changes by $9.5 \,mA$. Then the base current is (in $\,mA$)

In a transistor circuit,the emitter-base circuit of a $n-p-n$ transistor is always

In a common base amplifier circuit,calculate the change in base current if the change in emitter current is $2\, mA$ and $\alpha = 0.98$.

When $n-p-n$ transistor is used as an amplifier :

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.

The input resistance of a common-emitter amplifier is $2 \, k\Omega$ and a.c. current gain is $20$. If the load resistor used is $5 \, k\Omega$,calculate the transconductance of the transistor used in $\Omega^{-1}$.