$AM$ is used for broadcasting because...

The maximum amplitude of an $AM$ wave is $90 V$ and the minimum amplitude is $10 V$. What is the original amplitude of the carrier wave in the given $AM$ wave in $V$?

Which of the following is the disadvantage of $FM$ over $AM$?

Which of the following options is $NOT$ correct? We need modulation for:

Match List $I$ with List $II$ :

List $I$	List $II$
$A$. Attenuation	$I$. Combination of a receiver and transmitter.
$B$. Transducer	$II$. Process of retrieval of information from the carrier wave at receiver.
$C$. Demodulation	$III$. Converts one form of energy into another.
$D$. Repeater	$IV$. Loss of strength of a signal while propagating through a medium.

Choose the correct answer from the options given below:

$A$ transmitting antenna is kept on the surface of the earth. The minimum height of the receiving antenna required to receive the signal in line-of-sight at $4\,km$ distance from it is $x \times 10^{-2}\,m$. The value of $x$ is (Let radius of earth $R = 6400\,km$).