The bells of a temple are made of large size. It is for

$(a)$ Why are sound waves called mechanical waves? List two practical applications of reflection of these waves.
$(b)$ $A$ stone is dropped from the top of a tower $125 \ m$ high into a pond of water at the base of the tower. When is the splash heard at the top? $(g = 10 \ m s^{-2}$ and speed of sound $= 340 \ m s^{-1})$

What is Galton's whistle? To what use can it be put?

$(a)$ Write two points of difference between sound wave and light wave.
$(b)$ Write an expression relating wave velocity, wavelength and frequency if speed of sound in air is $340 \, m s^{-1}$.
Calculate:
$(i)$ Wavelength when frequency $= 256 \, Hz$.
$(ii)$ Frequency when wavelength $= 0.85 \, m$.

Which of the following are transferred from one place to another place by the waves?

Explain how the human ear works in the transmission of sound waves to the brain.