For a transistor , `alpha_(dc)` and `beta_(dc)` are the current ratios, then the value of `(beta_(dc) - alpha_(dc))/(alpha_(dc) . beta_(dc))`

Options

A. 1
B. 1.5
C. 2
D. 2.5

Answer

A

Explanation

For the transistor
`beta_"dc"=alpha_"dc"/(1-alpha_"dc")`
`therefore 1-alpha_(dc) = alpha_(dc)/beta_(dc)`…(1)
`therefore(beta_"dc"-alpha_"dc")/(alpha_"dc"-beta_"dc")=(beta_"dc"(1-(alpha_"dc")/(beta_"dc")))/(alpha_"dc" beta_"dc")`
`=(1-alpha_"dc"/beta_"dc")/alpha_"dc"`
`=(1-(1-alpha_"dc"))/alpha_"dc"` ...from (1)
`=alpha_"dc"/alpha_"dc"=1` ...Option (a)