The process of the loss of strength of a signal while propagating through a medium is known as:

$A$ transmitting antenna is at a height of $50 \ m$ and the receiving antenna is at a height of $5 \ m$. What is the maximum communication range in $km$? (Take $R = 6400 \ km$)

During modulation,a transmitter supplies $9 \ kW$ to the antenna. Calculate the total power radiated during $40\%$ modulation in $kW$.

If the maximum and minimum amplitudes of a modulated wave are $25 \ V$ and $5 \ V$ respectively,then the modulation index is

Assertion $(A)$: Television signals are received through sky-wave propagation.
Reason $(R)$: The ionosphere reflects electromagnetic waves of frequencies in the range $(3-30)$ $MHz$.
Choose the correct option.

$A$ $..........$ is used in the receiver section to reduce the magnitude of signals.