b
\({I_c} = 120\,mA,\,\,{I_b} = 2\,mA \Rightarrow \mathop {{I_e} = {I_b} + {I_c}}\limits_{(emitter\,current)} \)

\(\Rightarrow \mathrm{I}_{\mathrm{e}}=120+2=122 \,\mathrm{mA}\)

Resistance gain \(=3\)

\(d.c\) power gain \(=(\text { current gain })^{2} \times\) resistance gain

\(=\left(\frac{\mathrm{I}_{\mathrm{c}}}{\mathrm{I}_{\mathrm{b}}}\right)^{2} \times\) resistance gain

\(=\left(\frac{120}{2}\right)^{2} \times 3\)

\(=(60)^{2} \times 3=3600 \times 3=10800\)