For efficient transmission of sound waves of wavelength $\lambda$,the minimum length of the antenna should be.....

$A$ $..........$ is used in the receiver section to reduce the magnitude of signals.

The bandwidth of an audio signal is approximately:

In amplitude modulation,the amplitude of the $.......$ wave varies in proportion to the instantaneous value of the $.......$ wave.

$A$ transmitting antenna is at a height of $50 \ m$ and the receiving antenna is at a height of $5 \ m$. What is the maximum communication range in $km$? (Take $R = 6400 \ km$)

$A$ carrier signal of frequency $v_1$ and peak voltage of $V_1$ is modulated by a message signal of frequency $v_2$ and peak voltage of $V_2$. Let $m$ be the modulation index and $v_{+}, v_{-}$ be side bands produced. The correct statement is