$A$ $TV$ transmission tower of height $h$ covers a range of distance $d$. By how much will the range change if the height is increased to $3/2 h$?

The process of retrieval of information from the carrier wave is known as:

$A$ 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.......$V$

$A$ radar has a power of $1 \text{ kW}$ and operates at a frequency of $10 \text{ GHz}$. If it is located on top of a mountain at a height of $500 \text{ m}$,what is the maximum distance in $\text{km}$ up to which it can detect objects on the Earth's surface? (Radius of the Earth $R = 6.4 \times 10^{6} \text{ m}$)

Which of the following is the communication channel in case of radio communication?

For an amplitude-modulated wave,the maximum amplitude is $9 \ V$ and the minimum amplitude is $3 \ V$. The modulation index is ........$\%$.