The current gain in the common emitter mode of a transistor is 10. The input impedance is `20kOmega` and load of resistance is `100k Omega`. The power gain is

Options

A. 300
B. 500
C. 200
D. 100

Answer

B

Explanation

The power gain is defined as the ratio of charge in output power to the charge in input power.
Since, `P=Vi`
therefore
Power gain = current gain `xx` voltage gain
`=beta xx beta ((R_("out"))/(R_("in")))=beta^(2)((R_("out"))/(R_("in")))`
Given, `beta=10, R_("in") =20kOmega and R_("out")=100kOmega`
`therefore" Power gain"=(10)^(2)((100)/(20))=100xx5=500`