For a common emitter amplifier, the voltage gain is 40. Its input and output impedances are 100 `Omega` and 400 `Omega` respectively. The power gain of the C.E. amplifier will be
A. 300
B. 400
C. 450
D. 500
A. 300
B. 400
C. 450
D. 500
Correct Answer – B
40=Current gain x `400/100`
`therefore ` Current gain = 10
`therefore` Power gain = Voltage gain x Current gain = 400