Ground waves are polarized in which direction?

The frequency of a carrier wave is $1 MHz$. It is modulated by a wave of frequency $10 kHz$. If their amplitudes are $10 V$ and $0.5 V$ respectively,what are the modulation index and the frequencies of the $USB$ and $LSB$?

For a television network,$5 \times 10^5$ channels are granted. If the central frequency of the microwave link is $25 \text{ GHz}$ and the allotted bandwidth for each channel is $2 \text{ kHz}$,then what percentage of the link is used for the network (in $\%$)?

Radio waves of constant amplitude are produced by a/an . . . . . . .

Which of the following modulated signals has the best noise tolerance?

$A$ $100\, V$ carrier wave is made to vary between $160\, V$ and $40\, V$ by a modulating signal. What is the modulation index?