For an amplitude modulated wave,the maximum and minimum amplitudes are $12 \,V$ and $3 \,V$ respectively. Then the modulation index is

If the frequencies of the carrier wave and message signal are $1 \text{ MHz}$ and $28 \text{ kHz}$ respectively,then the frequencies of the side bands are

The process of superimposing low-frequency signals onto high-frequency carrier waves is called ..........

$A$ message signal is used to modulate a carrier signal of frequency $5 MHz$ and peak voltage of $40 V$. In the process,two side-bands are produced separated by $40 kHz$. If the modulation index is $0.75$,then the peak voltage and frequency of the message signal,respectively,are:

In which of the following is the remote sensing technique $NOT$ used?

$A$ radio can tune to any station in the $6\,MHz$ to $10\,MHz$ band. The value of the corresponding wavelength bandwidth will be $....\,m$.