The circuit used to separate information signals from the carrier wave is called a .......

What should be the height of the transmitting antenna and the population covered if the television telecast is to cover a radius of $150 \, km$? The average population density around the tower is $2000 \, / km^2$ and the value of $R_e = 6.5 \times 10^6 \, m$.

The electron density of the ionospheric layer is $10^{11} \ m^{-3}$. Communication waves of frequency up to $f_c$ $MHz$ will be reflected by the ionospheric layer. Find $f_c$.

$A$ message signal of peak voltage $12 \ V$ is used to amplitude modulate a carrier signal of frequency $1.2 \ MHz$. The amplitude of the side bands is (in $V$)

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

The radio horizon of a transmitting antenna of height $39.2 \ m$ is (Radius of the earth $= 6400 \ km$) (in $km$)