If a receiving station on the ground is receiving a frequency of $10 \text{ MHz}$, the mode of propagation is...

Radio waves that reach the receiver after being reflected from the ionosphere propagate via .......

$A$ bandwidth of $6 \, \text{MHz}$ is available for $A.M.$ transmission. If the maximum audio signal frequency used for modulating the carrier wave is not to exceed $6 \, \text{kHz}$,the number of stations that can be broadcasted within this band simultaneously without interfering with each other will be ..... .

The maximum number of $TV$ signals that can be transmitted along a coaxial cable is

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 $km$)

What is an analog signal?