In amplitude modulation,the amplitude of the $.......$ wave varies in proportion to the instantaneous value of the $.......$ wave.

Long range radio transmission is possible when the radio waves are reflected from the ionosphere. For this to happen,the frequency of the radio waves must be in the range:

The mathematical form of an $AM$ wave is given by $e = 50 (1 + 0.5 \sin (2\pi \times 5 \times 10^{3}) t) \sin (31.4 \times 10^{6}) t \, V$. To generate this $AM$ wave,the amplitudes of the carrier wave and the modulating wave must be,respectively,....... and ....... .

An amplitude modulated wave is represented by $V_{AM} = 10[1 + 0.4 \cos(2 \pi \times 10^4 t)] \cos(2 \pi \times 10^7 t) \text{ V}$. The total bandwidth of the amplitude modulated wave is:

In a communication system,noise is most likely to affect the signal:

Which of the following statements is $NOT$ correct?