The transmission loss per kilometer in an optical fiber is approximately...........$dB$.

$A$ message signal of frequency $10 kHz$ is used to modulate a carrier wave of frequency $6 MHz$. The sideband frequencies are:

The $TV$ transmission tower at a particular station has a height of $125\, m$. For doubling the coverage range,the height of the tower should be increased by .............$m$.

Which of the following is a man-made signal?

For $100\%$ modulation $(AM)$,the useful part of the total power radiated is

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