A charge of 8.0 mA in the emitter current brings a charge of 7.9 mA in the collector current. The values of `alpha and beta` are

Options

A. `0.99, 90 `
B. `0.96, 79 `
C. `0.97, 99 `
D. `0.99, 79 `

Answer

D

Explanation

Given that, change in emitter current, `Delta I_(E) = 8` mA and change in collector current, `Delta I_(C ) = 7.9` mA.
We know that,
`alpha = (DeltaI_(C ))/(DeltaI_(E))`
`implies alpha = (7.9)/(8) `
`implies alpha ~~ 0.99 `
Also we know that
`beta = (alpha)/(1-alpha)`
`implies beta = ((7.9)/(8))/(1-(7.9)/(8))=(7.9)/(8.-7.9)`
`implies beta = (7.9)/(0.1) = 79`
Hence, the required answer is
`alpha = 0.99 ` and `beta = 79` .