Sound travels in air if

$(a)$ What is meant by intensity of sound?
$(b)$ Mention the conditions for an echo to be heard clearly.
$(c)$ $A$ ball is dropped into a pond from a height of $44.1 \, m$. The splash of sound is heard $3.13 \, s$ after the ball is dropped. Determine the velocity of sound in air.

The speed of sound is $310 \, m s^{-1}$. $A$ person fires a gun and the echo is heard after $1.5 \, s$. Calculate the distance of the person from the cliff from which the echo takes place. (in $, m$)

Define the following characteristics of sound:
$(a)$
$(i)$ Pitch
$(ii)$ Loudness
$(iii)$ Quality or Timbre
$(b)$ $A$ boy receives his echo $3 \, s$ later. Find the distance of the reflecting surface from the boy. Speed of sound in air is $342 \, m s^{-1}$.

If the frequency of a tuning fork is $400 \, Hz$ and the speed of sound in air is $340 \, m/s$. Find how far sound travels when the tuning fork makes $16$ vibrations. (in $m$)

State whether the following statement is true or false:
The audible range of frequencies for human beings is $20 \, Hz - 20 \, kHz$.