V=DistancetimeV = \frac{\text{Distance}}{\text{time}}V=timeDistance
= 50 cm2 s\frac{50\,\text{cm}}{2\,\text{s}}2s50cm
= 25 cms−1^{-1}−1.
f=Vλf = \frac{V}{\lambda}f=λV
f=255f = \frac{25}{5}f=525
= 5 Hz
