$A$ carrier wave of peak voltage $15 \,V$ is used to transmit a message signal. If the modulation index is $60 \%$, then the peak voltage of the modulating signal is (in $\,V$)

The radio horizon of a transmitting antenna of height $39.2 \ m$ is (Radius of the earth $= 6400 \ km$) (in $km$)

$A$ $500\, Hz$ modulating voltage fed into an $FM$ generator produces a frequency deviation of $2.25\, kHz$. If the amplitude of the voltage is kept constant but the frequency is raised to $6\, kHz$,then the new frequency deviation will be.......$kHz$.

Which of the following is true for communication via optical fiber?

$A$ $T$.$V$. tower has a height of $100 \, m$. The average population density around the tower is $1000 \, km^{-2}$ and the radius of the earth is $6.37 \times 10^6 \, m$. The population covered is

If a message signal of frequency $10 kHz$ and peak voltage $12 V$ is used to modulate a carrier wave of frequency $1 MHz$, the modulation index is $0.6$. To make the modulation index $0.75$, the carrier peak voltage should be