Physics - Semiconductors Question with Solution | TestHub

The power gain is defined as the ratio of change in output power and the change in input power.
Since, $\mathrm{P}=\mathrm{VI}$.

Therefore, Power gain = Current gain X Voltage gain
$=\mathrm{\beta }\times \mathrm{\beta }\left(\frac{{\mathrm{R}}_{\mathrm{out}}}{{\mathrm{R}}_{\mathrm{in}}}\right)={\mathrm{\beta }}^2\left(\frac{{\mathrm{R}}_{\mathrm{out}}}{{\mathrm{R}}_{\mathrm{in}}}\right)$

Given, $\mathrm{\beta }=10$, ${\mathrm{R}}_{\mathrm{in}}=20\mathrm{ }\mathrm{k\Omega }$ and ${\mathrm{R}}_{\mathrm{out}}=100\mathrm{ }\mathrm{k\Omega }$.
Hence, Power gain $={\left(10\right)}^2\left(\frac{100}{20}\right)=100\times 5=500$