Read the passage and answer the question.

A junction diode cannot be used for amplification so another type of semiconductor device, a transistor, is used. It is a three section semiconductor with three sections being the emitter, the collector and the base. Common emitter characteristics of a transistor are graphs that are obtained between voltage and current, when emitter is earthed, base is used as input terminal and collector as the output terminal.

If the base current rises by 250 μA when the collector current increases from 2.5 mA to 6.0 mA, what will the current gain be?

14

$\text{Current gain }\beta = \frac{\Delta I_C}{\Delta I_B} = \frac{3.5mA}{0.25mA} = 14$