The height of the transmitting antenna, if $TV$ programs have to cover a population in an area of radius $64 \ km$, is: [Use Radius of earth $= 6.4 \times 10^6 \ m$] (in $m$)

If the amplitude of an audio signal is half the amplitude of the carrier wave,what is the modulation index?

In an $FM$ system, a $7 \ kHz$ signal modulates a $108 \ MHz$ carrier such that the frequency deviation is $50 \ kHz$. The carrier swing is: (in $kHz$)

An $AM$ wave has $1800 \ W$ of total power content. For $100 \%$ modulation,the carrier should have a power content equal to $...... \ W$.

If a message signal of frequency $f_{m}$ is amplitude modulated with a carrier signal of frequency $f_{c}$ and radiated through an antenna,the wavelength of the corresponding signal in air is ....... .

$A$ carrier wave of peak voltage $20 V$ is used to transmit a message signal. For getting a modulation index of $60 \%$, the peak voltage of the modulating signal is (in $V$)