If `beta, R_L and r` are the ac current gain, load resistance and the input resistance of a transistor respectively in CE configuration, the voltage and the power gains respectively are

Options

A. `betaR_L/r and beta^2 R_L/r`
B. `beta r/R_L and beta^2 r/R_L`
C. `beta R_L/r and beta(R_L/r)^2`
D. `beta r/R_L and beta(r/R_L)^2`

Answer

A

Explanation

Voltage gain = current gain x resistance gain `=betaxx("output resistance")/("input resistance")=betaxxR_L/r`
Power gain = voltage gain x current gain `=betaR_L/rxxbeta=beta^2R_L/r`