# Speed of Waves

### Speed of Water Waves

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

vs = speed of wave in deep region
λs = speed of wave in deep region