A ripple tank is used to study water waves produced by a small electric vibrator.
(i) The distance between two successive crests is measured to be 25cm and the vibrator is known to complete 8 oscillations each second. Calculate the speed of these water waves.
(ii) The vibrator speed is increased so that it now completes 12 oscillations per second while the speed of the waves in water is unchanged. Calculate the new wavelength of the waves.
(iii) Briefly state why the wavelength changes when the frequency is altered even though the speed of the waves in the medium remains constant.