For an $FM$ carrier with a carrier frequency of $200 \text{ kHz}$ and a modulating frequency of $10 \text{ kHz}$,the modulation index is...

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

$A$ carrier wave $v_{c}(t) = 160 \sin(2 \pi \times 10^{6} t) \text{ V}$ is made to vary between $V_{\max} = 200 \text{ V}$ and $V_{\min} = 120 \text{ V}$ by a message signal $v_{m}(t) = A_{m} \sin(2 \pi \times 10^{3} t) \text{ V}$. The peak voltage $A_{m}$ of the modulating signal is ..... .

Sound waves cannot be transmitted directly after conversion into electrical waves because...

Three signals related to amplitude modulation are shown in the figure. The correct assignment of the signals is

The height of a transmitting antenna is $h \ m$ and the height of a receiving antenna is $45 \ m$. The distance between them is $40 \ km$. For satisfactory $Line\, of\, Sight$ $(LOS)$ communication between the two antennas,the height of the transmitting antenna $h$ must be ....... $m$. (Radius of the Earth $R = 6400 \ km$)