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

$A$ $TV$ transmitter has a range of $50 \ km$. The height of the $TV$ transmitter is $......$ (Radius of the earth $R_e = 6.4 \times 10^6 \ m$) (in $m$)

If a $TV$ transmission antenna covers a radius of $128 \, km$,what should be the height of the antenna in $m$?

$A$ carrier wave of peak voltage $10 \,V$ is used to transmit a message signal. What should be the peak voltage of the modulating signal in order to have a modulation index of $80 \%$ (in $\,V$)?

When the receiving antenna is on the ground,the range of a transmitting antenna of height $980 \ m$ is (Radius of the earth $= 6400 \ km$) (in $km$)

Choose the correct statement for amplitude modulation.