What is the modulation index of the $AM$ wave shown in the figure?

Match List-$I$ with List-$II$:

List-$I$	List-$II$
$A$. $AM$ Broadcast	$I$. $88-108\,MHz$
$B$. $FM$ Broadcast	$II$. $540-1600\,kHz$
$C$. Television	$III$. $3.7-4.2\,GHz$
$D$. Satellite Communication	$IV$. $54-890\,MHz$

Choose the correct answer from the options given below:

In communication with the help of an antenna,if the height is doubled,then the range covered,which was initially $r$,would become:

The maximum and minimum voltage of an amplitude modulated signal are $60\,V$ and $20\,V$ respectively. The percentage modulation index will be $....\%$

$A$ transmitting and receiving antenna have a height of $d$ meters each. The maximum distance between them for satisfactory communication in Line-of-Sight $(LOS)$ mode is $2d$ kilometers. If the radius of the Earth is $6400 \text{ km}$, then the value of $d$ is: (in $\text{ m}$)

$A$ transmitting antenna at the top of a tower has a height of $50\, m$ and the height of the receiving antenna is $80\, m$. What is the range of communication for Line of Sight (LoS) mode? (In $km$)
[Use radius of earth $R = 6400\, km$]