What type of modulation is employed in India for radio transmission?

$A$ radar has a power of $1 \ kW$ and is operating at a frequency of $10 \ GHz$. It is located on a mountain top of height $500 \ m$. The maximum distance up to which it can detect an object located on the surface of the earth (Radius of earth $= 6.4 \times 10^6 \ m$) is ....... $km$.

The maximum amplitude of an $AM$ wave is found to be $20 \,V$ while its minimum amplitude is $4 \,V$. The modulation index is

$A$ carrier wave has a frequency of $1000 \, kHz$ and an amplitude of $20 \, V$. It is amplitude modulated by a signal wave of frequency $10 \, kHz$ and amplitude $10 \, V$. The modulation index and the frequencies of the $LSB$ and $USB$ are,respectively:

$A$ carrier wave of peak voltage $14\,V$ is used for transmitting a message signal. The peak voltage of the modulating signal required to achieve a modulation index of $80\%$ will be.......$V$

The waves used for line-of-sight $(LOS)$ communication are