Question

For $100$% modulation (AM) the useful part of the total power radiated is

• A. $\frac{1}{2}$ of the total power
• B. $\frac{1}{3}$ of the total power
• C. $\frac{1}{4}$ of the total power
• D. $\frac{2}{3}$ of the total power

Answer 1

The correct option is B $\frac{1}{3}$ of the total power

$100$% modulation $\Rightarrow$ $m_a=1$
$\frac{Usefulpower}{Totalpowerradiated}=\frac{m_a^2}{2+m_{a^2}}$
$=\frac{1}{1+2}=\frac{1}{3}$

$\Rightarrow$ Useful power$=\frac{1}{3}$ (total power radiated)