The modulation index of an $FM$ carrier having a carrier swing of $200\, kHz$ and a modulating signal frequency of $10\, kHz$ is:

In $AM$ transmission,the bandwidth of transmission is $10 \, kHz$ and the carrier frequency is $100 \, kHz$. The sideband frequencies are given by:

The relationship between the maximum electron density $(N_{max})$ of the ionosphere and the critical frequency $(f_c)$ is given by:

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

An information signal of frequency $10 \text{ kHz}$ is modulated with a carrier wave of frequency $3.61 \text{ MHz}$. The upper sideband and lower sideband frequencies are:

$A$ $500\, Hz$ 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.......$kHz$.