For a transistor,$\alpha_{dc}$ and $\beta_{dc}$ are the current ratios,then the value of $\frac{\beta_{dc}-\alpha_{dc}}{\alpha_{dc} \times \beta_{dc}}$ is:

In a silicon transistor,a change of $7.89 \, mA$ in the emitter current produces a change of $7.8 \, mA$ in the collector current. What change in the base current is necessary to produce an equivalent change in the collector current (in $mA$)?

In a common base amplifier,the phase difference between the input and output voltage is .......

Assertion: $A$ transistor amplifier in common emitter configuration has a low input impedance.
Reason: The base-to-emitter region is forward-biased.

An oscillator is nothing but an amplifier with