A transistor connected in the common-emitter configuration has a base current of 50 µA and a collector current of 5 mA. What is the current gain (β) of the transistor?

The current gain β = Ic/Ib = 5 mA / 50 µA = 5 × 10⁻³ / 50 × 10⁻⁶ = 100. A β of 100 is typical for many bipolar junction transistors. Distractors arise from unit conversion errors or inverting the ratio.