Frequencies in the $UHF$ range normally propagate by means of:

$A$ $TV$ 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 $m$)?

Given below in the left column are different modes of communication using the kinds of waves given in the right column.

$A$. Optical Fiber Communication	$P$. Ultrasound
$B$. Radar	$Q$. Infrared Light
$C$. Sonar	$R$. Microwaves
$D$. Mobile Phones	$S$. Radio Waves

From the options given below, find the most appropriate match between entries in the left and the right column.

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

For sky wave propagation,the radio waves must have a frequency range in between

The total power content of an $AM$ wave is $1500 \, W$. For $100 \%$ modulation,the power transmitted by the carrier is ........ $W$.