The value of current gain `alpha` of trasistor is `0.98`. The value of `beta` will be

Options

A. 490
B. 4.9
C. 59
D. 49

Answer

D

Explanation

(d) Current gain `alpha` is the ratio of change in collector current to the change in emitter current, while current gain `beta` is the ratio of change in collector current ot change in base current.
Current gains are given by
`alpha = (Delta i_(C))/(Delta i_(E))` and `beta = (Delta i_(C))/(Delta i_(B))`
where `Delta i_(C ), Delta i_(E), Delta i_(B)`a re change in collector current, emitter current and base current respectively. The relation between `alpha` and `beta` is
`beta = (alpha)/(1 - alpha)`
Given, `alpha = 0.98`, hence we have
`beta = (0.98)/(1 - 0.98) = 49`