For a transistor in $CE$ mode to be used as an amplifier,it must be operated in:

$NPN$ transistors are preferred to $PNP$ transistors because they have

In the study of a transistor as an amplifier,if $\alpha = \frac{I_{C}}{I_{E}}$ and $\beta = \frac{I_{C}}{I_{B}}$,where $I_{C}$,$I_{B}$,and $I_{E}$ are the collector,base,and emitter currents respectively,then:

In a $CE$ circuit,the collector of a transistor is kept at a constant voltage $V_C = 1.5 \ V$. When the base current changes from $100 \ \mu A$ to $150 \ \mu A$,the collector current changes from $5 \ mA$ to $10 \ mA$. The current gain $\beta$ for this transistor is:

In a common emitter transistor amplifier,the output voltage and input voltage have a phase difference of

If $R_C$ and $R_B$ are respectively the resistances of the collector and base sides of the circuit,and $\beta$ is the current amplification factor,then the voltage gain of a transistor amplifier in common emitter configuration is