What do you understand by the term sound energy?

How do the frequency and amplitudes affect a musical sound?

What is 'Ultrasound'? Explain how defects in a metal block can be detected using ultrasound.

State the relationship between frequency and time period of a wave. The wavelength of vibrations produced on the surface of water is $2 \, cm$. If the wave velocity is $16 \, m s^{-1}$, find its frequency and time period.

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 $342 \, m s^{-1}$.

State whether the following statement is true or false: Sound and light travel in a medium in the form of crests and troughs and rarefactions and compressions respectively.