WAEC - Physics (2020 - No. 38)
Water waves have a wavelength of 3.6cm and speed of 18cms\(^{-1 }\) in deep water. If the waves enter shallow water with wavelength of 2.0cm, calculate the speed of the waves in the shallow water.
0.4cms\(^{-1}\)
2.5cms\(^{-1}\)
10.0cms\(^{-1}\)
10.8cms\(^{-1}\)
설명
Velocity = frequency x wavelength
v = 18cm/s, wavelength = 3.6cm, then F = 5hertz
therefore, the speed of the wave in the shallow water = 5 x 2 = 10cm/s
NOTE; as a general rule, the frequency of a wave remains constant while speed and wavelength change as it travels from one medium to another.