$A$ carrier wave of peak voltage $20 V$ is used to transmit a message signal. For getting a modulation index of $60 \%$, the peak voltage of the modulating signal is (in $V$)

The mathematical form of an $AM$ wave is given by $e = 50 (1 + 0.5 \sin(2\pi \times 5 \times 10^{3} t)) \sin(31.4 \times 10^{6} t) \text{ volts}$. Which of the following frequencies is absent in the given $AM$ wave?

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

List-$I$	List-$II$
$A$. Television signal	$I$. $03\,KHz$
$B$. Radio signal	$II$. $20\,KHz$
$C$. High Quality Music	$III$. $02\,MHz$
$D$. Human speech	$IV$. $06\,MHz$

Choose the correct answer from the options given below:

Audio signals cannot be transmitted directly over long distances because:

An audio signal $v_{m} = 20 \sin(2 \pi \times 1500 t)$ amplitude modulates a carrier $v_{c} = 80 \sin(2 \pi \times 100,000 t)$. The value of percent modulation is..........

If a receiving station on the ground is receiving a frequency of $10 \text{ MHz}$, the mode of propagation is...