Given:
Voltage gain, Av=50
Input impedance, Ri=100 Ω
Output impedance, Ro=200 Ω
The power gain (Ap) of an amplifier is given by the ratio of output power to input power:
Ap=PinPout=Vin2/RiVout2/Ro=(VinVout)2×RoRi
Since Av=VinVout, we have:
Ap=Av2×RoRi
Substituting the given values:
Ap=(50)2×200100
Ap=2500×21=1250
Alternatively, we can first find the current gain (β):
Av=β×RiRo
50=β×100200⟹β=25
Then, Power Gain = Voltage Gain × Current Gain:
Ap=Av×β=50×25=1250