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

$A$ $TV$ 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:

The bandwidth of an audio signal is approximately:

If the sum of heights of transmitting and receiving antennas in line of sight communication is $h$,then the height of the receiving antenna,to have the maximum range,is

Which of the following four alternatives is not correct? We need modulation:

$A$ $TV$ tower has a height of $160 \,m$. Its coverage range is nearly (Earth's radius,$R_e = 6400 \,km$):