For television broadcasting,the frequency employed is normally in the range of,

$A$ message signal of frequency $8 \text{ kHz}$ and peak voltage $12 \text{ V}$ is used to modulate a carrier of frequency $1.2 \text{ MHz}$ and peak voltage $20 \text{ V}$. The modulation index is

The maximum amplitude of an $AM$ wave is $90 \ V$ and the minimum amplitude is $10 \ V$. What is the modulation index of the $AM$ wave in percentage?

$A$ message signal of frequency $3\,kHz$ is used to modulate a carrier signal of frequency $1.5\,MHz$. The bandwidth of the amplitude modulated wave is

The heights of transmitting and receiving antennas are respectively $\frac{1}{20000}$ and $\frac{1}{80000}$ times the radius of the earth. The maximum distance between these two antennas for satisfactory communication in line of sight mode is (Radius of the earth $= 6.4 \times 10^6 \ m$) (in $km$)

$A$ sinusoidal wave $y(t) = 40 \sin(10 \times 10^6 \pi t)$ is amplitude modulated by another sinusoidal wave $x(t) = 20 \sin(1000 \pi t)$. The amplitude of the minimum frequency component of the modulated signal is ...........