State whether the following statement is true or false:
The frequency of a sounding body with a time period of $0.01 \, s$ is $100 \, Hz$.

Will the sound be audible if a string is set into vibration on the surface of the moon? Give a reason for your answer.

Which of the above two graphs $(a)$ and $(b)$ representing the human voice is likely to be the male voice? Give reason for your answer.

Represent graphically by two separate diagrams in each case:
$(i)$ Two sound waves having the same amplitude but different frequencies.
$(ii)$ Two sound waves having the same frequency but different amplitudes.
$(iii)$ Two sound waves having different amplitudes and also different wavelengths.

$A$ man stands between two high-rise buildings and blows a whistle. He hears two successive echoes after $0.4 \, s$ and $2.0 \, s$. Calculate the distance between the buildings. (Assume the speed of sound $v = 332 \, m/s$)

If $20$ waves are produced per second,what is the frequency in hertz (in $, Hz$)?