If an explosion takes place at the bottom of a lake,what type of shock waves will be produced in the water?

$(a)$ List in tabular form the distinguishing features between longitudinal waves and transverse waves. Give an example of each.
$(b)$ State and define the characteristics associated with sound waves.

$A$ 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 $v = 332 \, m/s$)

An astronaut cannot hear his companion on the surface of the Moon because

$(i)$ Define the time period of a wave.
$(ii)$ Give the relation among speed of sound $V$,wavelength $\lambda$ and its frequency $\nu$.

Sound waves are