If $f_m$ is the modulation frequency for $FM$,then the modulation index is proportional to.....

$A$ basic communication system consists of:
$(A)$ Transmitter $(B)$ Information source $(C)$ User of information $(D)$ Channel $(E)$ Receiver
Choose the correct sequence in which these are arranged in a basic communication system.

Through which mode of propagation can radio waves be sent from one place to another?

Coaxial cable,a widely used wire medium,offers an approximate frequency bandwidth of:

$A$ transmitting antenna has a height of $320\, m$ and that of the receiving antenna is $2000\, m$. The maximum distance between them for satisfactory communication in line-of-sight mode is $d$. The value of $d$ is $\ldots \ldots \, km$.

The height of a transmitting antenna at the top of a tower is $25 \; m$ and that of the receiving antenna is $49 \; m$. The maximum distance between them for satisfactory communication in $LOS$ (Line of Sight) is $K \sqrt{5} \times 10^{2} \; m$. The value of $K$ is $\dots$ [Assume radius of Earth is $64 \times 10^{5} \; m$] (Calculate up to the nearest integer value).