During modulation,a transmitter supplies $9 \ kW$ to the antenna. Calculate the total power radiated during $40\%$ modulation in $kW$.

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 .............$m$.

Indicate which one of the following systems is digital.

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 ....... .

$A$ message signal of frequency $15 kHz$ is used to modulate a carrier of frequency $v_c$. If the side bands produced are $1515 kHz$ and $1485 kHz$,then $v_c$ is (in $MHz$)

An oscillator is producing $FM$ waves of frequency $2 \text{ kHz}$ with a frequency variation of $10 \text{ kHz}$. What is the modulation index?