An amplitude modulated voltage signal $x(t)$ drives a load of $1 \Omega$.
$$x(t)=K \cos (300 \pi \: t)+L \cos (240 \pi \: t)+L \cos (360 \pi \: t) .$$
If the efficiency is $60 \%$ and the carrier power is $50$ $\mathrm{W}$, the value of $L$ is $\_\_\_\_$ $\mathrm{V}$.
- $8.66$
- $1.22$
- $0.81$
- $17.32$
