$A$ wave is represented as $e = 10 \sin(10^8 t + 6 \sin(1250 t))$. The modulation index is:

An antenna is placed in a dielectric medium of dielectric constant $6.25$. If the maximum size of the antenna is $5.0 \, mm$,what is the minimum frequency of the signal it can radiate in $GHz$? (Given $\mu_{r} = 1$ for the dielectric medium)

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

Range of frequencies allotted for commercial $FM$ radio broadcast is

$A$ carrier wave of peak voltage $16 \text{ V}$ is used to transmit a signal. If the modulation index is $75 \%$, the peak voltage of the modulating signal is (in $\text{ V}$)

$A$ $TV$ transmitting antenna is $128 \ m$ tall. If the receiving antenna is at the ground level,the maximum distance between them for satisfactory communication in line-of-sight mode is (radius of the earth $R_e = 6.4 \times 10^6 \ m$):