$A$ carrier wave of amplitude $15\,V$ is modulated by a sinusoidal baseband signal of amplitude $3\,V$. The ratio of maximum amplitude to minimum amplitude in an amplitude modulated wave is:

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

The waves which are reflected back to the earth by the ionosphere are:

Which type of medium is used for optical communication?

The modulation frequency of an $AM$ radio station is $250\, kHz$,which is $10\%$ of the carrier wave. If another $AM$ station approaches you for license,what broadcast frequency will you allot? (Note: The interval between two carrier frequencies should be at least two times the modulation frequency to avoid interference.)

The range of frequency bands used for standard $AM$ broadcast is