Question-41 In an n-p-n transistor amplifier, the collector current is 8\ mA. If 80\% of the electrons from the emitter reach the collector, then (\alpha and \beta are current ratios)
(A) the base current is 20\ mA.
(B) the emitter current is 2\ mA.
(C) \alpha=0.8,\ \beta=4.0
(D) \alpha=4.0,\ \beta=0.8
Answer : (C)
Explanation:
α = \frac{I_C}{I_E} = \frac{8}{10} = 0.8
β = \frac{\alpha}{1 - \alpha} = \frac{0.8}{1 - 0.8}
∴ β = 4