Physics (AS & A Level) · Feb / March 2016 · Paper 12 · Question 24

The diagram represents the pattern of stationary waves formed by the superposition of sound waves from a loudspeaker and their reflection from a metal sheet (not shown). W, X, Y and Z are four points on the line through the centre of these waves. Which statement about these stationary waves is correct?

1. AAn antinode is formed at the surface of the metal sheet.
2. BA node is a quarter of a wavelength from an adjacent antinode.
3. CThe oscillations at X are in phase with those at Y.
4. DThe air particles oscillate perpendicular to the line WZ.

As printed in the paper