$A$ carrier is simultaneously modulated by two sine waves with modulation indices of $0.4$ and $0.3$. The resultant modulation index will be

$A$ telephone link operating at a central frequency of $10\, GHz$ is established. If $1\%$ of this is available,then how many telephone channels can be simultaneously provided,given that each telephone covers a bandwidth of $5\, kHz$?

$A$ modulating signal $2 \sin (6.28 \times 10^{6} t)$ is added to the carrier signal $4 \sin (12.56 \times 10^{9} t)$ for amplitude modulation. The combined signal is passed through a non-linear square law device. The output is then passed through a band pass filter. The bandwidth of the output signal of the band pass filter will be $MHz$.

$A$ signal emitted by an antenna from a certain point can be received at another point on the Earth's surface in the form of:

The amplitude of the side bands of the modulated signal, if the carrier signal and message signal amplitudes are $25 \,V$ and $5 \,V$ respectively, is (in $\,V$)

The antenna current of an $AM$ transmitter is $8 \ A$ when only the carrier is sent,but it increases to $8.96 \ A$ when the carrier is modulated by a sine wave. The percentage of modulation is: (in $\%$)