$A$ 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 $V$)

If the maximum and minimum amplitudes of a modulated wave are $25 \ V$ and $5 \ V$ respectively,then the modulation index is

The bandwidth of a coaxial cable system is approximately........ $MHz$.

$A$ message signal of frequency $15 kHz$ is used to modulate a carrier of frequency $v_c$. If the side bands produced are $1515 kHz$ and $1485 kHz$,then $v_c$ is (in $MHz$)

The government has divided the frequency range from $30\ MHz$ to $60\ MHz$ between $20$ stations,which are independently beaming their signals. Which of the signals can be beamed by each of the stations?

Space wave propagation is possible for which frequency range?