It is called vaporization. Vaporization is the phase transition from a liquid to a gas by means of evaporation or boiling. Evaporation occurs at temps below the boiling point and occurs on the liquids surface. Boiling is a rapid vaporization that occurs above the boiling temp and below or at the liquids surface.
Velocity (unit:m/s) of the wave is given with the formula:
v=f∧,
where f is the frequency which tells us how many waves are passing a point per second (unit: Hz) and ∧ is the wavelength, which tells us the length of those waves in metres (unit:m)
f=1/T , where T is the period of the wave.
In our case: f=1/3
∧=v/f=24m/s/1/3=24*3=72m
