### Speed of Water Waves

- When straight waves pass from deep to shallow water, their
- wave-length becomes shorter
- speed decreases
- frequency remain unchanged
- This can be illustrated by placing a piece of rectangular Perspex of suitable thickness in the tank to reduce the local water depth.
- Figure below shows the wavefront diagram of the wave formed.
- We can see that the wavelength above the Perspex is shallower.
- The relationship between the speed and wavelength of the wave in deep and shallow region is given by the formula below.
$$\frac{{v}_{d}}{{\lambda}_{d}}=\frac{{v}_{s}}{{\lambda}_{s}}$$
v
_{d}= speed of wave in deep regionλ_{d}= speed of wave in deep regionv_{s}= speed of wave in deep regionλ_{s}= speed of wave in deep region