In an amplitude modulator circuit,the carrier wave is given by $C(t) = 4 \sin(20000 \pi t)$ and the modulating signal is given by $m(t) = 2 \sin(2000 \pi t)$. The values of the modulation index and the lower sideband frequency are:

What is the advantage of an optical fibre?

Given below are two statements:
Statement-$I$: $A$ speech signal of $2 \, kHz$ is used to modulate a carrier signal of $1 \, MHz$. The bandwidth requirement for the signal is $4 \, kHz$.
Statement-$II$: The sideband frequencies are $1002 \, kHz$ and $998 \, kHz$.
In the light of the above statements,choose the correct answer from the options given below:

The heights of the transmitting and receiving antennas are $33.8 \ m$ and $64.8 \ m$ respectively. The maximum distance between the antennas for satisfactory communication in a line of sight mode is (Radius of the earth $= 6400 \ km$) (in $km$)

If a carrier wave $C(t) = A \sin \omega_c t$ is amplitude modulated by a modulating signal $m(t) = A \sin \omega_m t$,then the equation of the modulated signal $[C_m(t)]$ and its modulation index are respectively:

$A$ signal is to be transmitted through a wave of wavelength $\lambda$,using a linear antenna. The length $l$ of the antenna and effective power radiated $P_{eff}$ will be given respectively as: ($K$ is a constant of proportionality)