The diagram shows the arrangement of stationary waves produced by the superposition of sound waves from a loudspeaker and the waves reflected from a metal sheet (not shown). W, X, Y and Z are four points on the line passing through the centre of these waves. Which statement about these stationary waves is correct?
- AAn antinode is formed at the surface of the metal sheet.
- BA node is a quarter of a wavelength from an adjacent antinode.
- CThe oscillations at X are in phase with those at Y.
- DThe air particles oscillate perpendicular to the line WZ.