An audio signal consists of two distinct sounds: one is a human speech signal in the frequency band of $200\,Hz$ to $2700\,Hz,$ while the other is a high-frequency music signal in the frequency band of $10200\,Hz$ to $15200\,Hz.$ The ratio of the $AM$ signal bandwidth required to send both the signals together to the $AM$ signal bandwidth required to send just the human speech is

$A$ carrier wave of peak voltage $12 \, V$ 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 $75 \%$? ...... $V$

The transmission loss per kilometer in an optical fiber is approximately...........$dB$.

This question has Statement-$1$ and Statement-$2$. Of the four choices given after the statements, choose the one that best describes the two statements.
Statement-$1$: Sky wave signals are used for long-distance radio communication. These signals are, in general, less stable than ground wave signals.
Statement-$2$: The state of the ionosphere varies from hour to hour, day to day, and season to season.

What is the bit rate in $bits/sec$ for a signal with $16$ quantization levels and a sampling rate of $8 \, kHz$?

$A$ 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 $R = 6400\, km$]