For effective transmission of a wave with frequency $3000 \text{ kHz}$,the minimum length of the antenna should be ...... $m$.

The number of amplitude modulated broadcast stations that can be accommodated in a $300\, kHz$ bandwidth for the highest modulating frequency of $15\, kHz$ is:

In a communication system,what is used to extend the range of a communication?

The $TV$ transmission tower at a particular station has a height of $125\, m$. For doubling the coverage range,the height of the tower should be increased by .............$m$.

$A$ transmitting antenna covers a range of $12.8 \ km$. Find the height of the antenna in $m$. (Radius of the Earth $= 6400 \ km$)

An oscillator is producing $FM$ waves of frequency $2 \text{ kHz}$ with a frequency variation of $10 \text{ kHz}$. What is the modulation index?