Modulation is a process of superposing

The amplitude of $15 \sin (1000 \pi t)$ is modulated by $10 \sin (4 \pi t)$ signal. The amplitude modulated signal contains frequency(ies) of
$A) 500 \text{ Hz}$
$B) 2 \text{ Hz}$
$C) 250 \text{ Hz}$
$D) 498 \text{ Hz}$
$E) 502 \text{ Hz}$
Choose the correct answer from the options given below:

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

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

When the angle of incidence is $74^{\circ}$,the critical frequency of the $F$ layer is $50 \text{ MHz}$. What is the Maximum Usable Frequency $(MUF)$ in $\text{ MHz}$ (in $.5$)?

If $f_m$ is the modulation frequency for $FM$,then the modulation index is proportional to.....