For an amplitude-modulated wave,the maximum amplitude is $9 \ V$ and the minimum amplitude is $3 \ V$. The modulation index is ........$\%$.

The attenuation in optical fibre is mainly due to

If the area covered by an $FM$ radio station is to be doubled,by what factor must the height of the antenna be increased?

$A$ modulated signal is given by $C_m(t) = A_c \sin \omega_c t + \mu A_c \sin \omega_m t \sin \omega_c t$,where $\mu$ is the modulation index. To keep the signal without distortion,the value of $\mu$ should be

In $AM$ transmission,the bandwidth of transmission is $10 \, kHz$ and the carrier frequency is $100 \, kHz$. The sideband frequencies are given by:

In amplitude modulation,