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

The frequency range suitable for beyond-the-horizon communication using sky waves is:

$A$ transmitting antenna is kept on the surface of the earth. The minimum height of the receiving antenna required to receive the signal in line-of-sight at $4\,km$ distance from it is $x \times 10^{-2}\,m$. The value of $x$ is (Let radius of earth $R = 6400\,km$).

For an amplitude modulated wave,the maximum amplitude is found to be $10 \,V$ while the minimum amplitude is found to be $4 \,V$. The modulation index is

The maximum number of $TV$ signals that can be transmitted along a coaxial cable is

$A$ telephonic communication service is working at a carrier frequency of $20 GHz$. Only $20 \%$ of it is utilized for transmission. If each channel requires a bandwidth of $5 kHz$,then the number of telephonic channels that can be transmitted simultaneously are