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

$A$ basic communication system consists of:
$(A)$ Transmitter $(B)$ Information source $(C)$ User of information $(D)$ Channel $(E)$ Receiver
Choose the correct sequence in which these are arranged in a basic communication system.

In amplitude modulation,the amplitude of the carrier wave is $A_c$ and that of the modulating signal is $A_m$. In practice,the ratio of $A_m$ to $A_c$ is kept less than or equal to $1$ to avoid:

In an $AM$ detector circuit,$R = 2 \text{ k}\Omega$ and $C = 1 \mu\text{F}$. This circuit will demodulate a carrier frequency of ......... $\text{kHz}$ effectively.

The heights of transmitting and receiving antennas are respectively $\frac{1}{20000}$ and $\frac{1}{80000}$ times the radius of the earth. The maximum distance between these two antennas for satisfactory communication in line of sight mode is (Radius of the earth $= 6.4 \times 10^6 \ m$) (in $km$)