What is the frequency range of signals that can be transmitted using a $Twisted\, pair\, wire$?

$A$ $TV$ tower has a height of $100 \ m$. The average population density around the tower is $1000 \ \text{per} \ km^2$. The radius of the earth is $6.4 \times 10^6 \ m$. The population covered by the tower is:

If the maximum and minimum voltage of an amplitude modulated wave are $V_{max}$ and $V_{min}$ respectively,then the modulation factor is:

$A$ $TV$ tower has a height of $150 \ m$. If the population density around the $TV$ tower is $10^3 \ km^{-2}$, then the population covered by the tower is (Radius of the earth, $R = 6.4 \times 10^6 \ m$). (in $\text{lakh}$)

Which type of propagation is used to transmit radio waves from one place to another?

An antenna uses electromagnetic waves of frequency $5 \text{ MHz}$. For proper working,the size of the antenna should be: