When the receiving antenna is on the ground,the range of a transmitting antenna of height $980 \ m$ is (Radius of the earth $= 6400 \ km$) (in $km$)

An antenna current of an $AM$ broadcast transmitter modulated by $50\%$ is $11\, A$. The carrier current is.........$A$.

$A$ $TV$ transmission antenna at a particular station has a height of $100 \, m$. By how much should the height of the antenna be increased to double its coverage range (in $m$)?

The height of a transmission antenna is $49 \,m$ and that of the receiving antenna is $64 \,m$. What should be the maximum distance between them for line of sight transmission (in $\,km$)?

The refractive index of the ionosphere:

$A$ message signal of frequency $10 kHz$ is used to modulate a carrier wave of frequency $6 MHz$. The sideband frequencies are: