Two waves, each of fixed amplitude, meet and form an interference pattern. In that pattern, there are minima at particular points where the displacement remains zero at every moment. Which statement best describes the two waves?
- AThey must be coherent and of the same amplitude.
- BThey must be coherent but not necessarily of the same amplitude.
- CThey must be of the same amplitude but not necessarily coherent.
- DThey must not be coherent or of the same amplitude.