If a transmitting antenna of height $105 \,m$ is placed on a hill, then its coverage area is (in $\,km^2$)

If multiple waves with modulation indices $n_1, n_2, n_3, ...$ modulate a carrier wave,what is the total modulation index of the resulting wave?

$A$ carrier signal $60 \sin(2\pi \times 10^6 t)$ is used to modulate an audio signal $15 \sin(300 \pi t)$. The depth of modulation is .......... $\%$.

If a radio receiver amplifies all frequency signals equally and well,it is said to have high . . . . . . .

The carrier frequency of a transmitter is provided by a tank circuit of a coil of inductance $49\,\mu H$ and a capacitance of $2.5\,nF$. It is modulated by an audio signal of $12\,kHz$. The frequency range occupied by the side bands is

The height of a $T.V.$ tower is $75 \ m$. What is the maximum distance in $km$ up to which $T.V.$ transmission can be received (in $.98$)? (Radius of the Earth $= 6.4 \times 10^6 \ m$).