If an emitter current is changed by 4 mA, the collector current changes by 3.5 mA. The value of β will be:

7
0.5
0.875
3.5

Correct answer: 7

Solution

alpha = dIc/dIe = 3.5/4 = 0.875. Then beta = alpha/(1-alpha) = 0.875/0.125 = 7 (equivalently dIc/dIb = 3.5/0.5 = 7). The stored value 0.875 is alpha, not beta.

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