In a transistor , the value of `alpha` veries between `(20)/(21) and (100)/(101)` . Then the value of `beta` varies between

Options

A. (10)-(10)
B. 0.95-0.99
C. 20-100
D. 200-300

Answer

C

Explanation

Current gain, `beta = Deltai_(c)/Deltai_(b)`
Change in collector current, `Deltai_(c) = (4 - 0.2)mA = 3.8 xx 10^(-3)`
Change in base current, `Deltai_(b) = (140 - 45)muA = 95 xx 10^(-6)A`
`:. beta = 3.8 xx 10^(-3)/95 xx 10^(-6) = 0.04 xx 10^(-3) = 40`