Physics (AS & A Level) · Oct / Nov 2024 · Paper 12 · Question 24

A progressive longitudinal sound wave moves through air. The diagram shows the positions of the air particles along part of the wave at one instant. Point Q is a distance x from point P. Which graph shows the variation of the displacement of the air particles with distance from P along the wave?

1. AGraph A: displacement against distance, single positive half-sine arch from 0 to x
2. BGraph B: displacement against distance, single negative half-sine arch from 0 to x
3. CGraph C: displacement against distance, full sine wave with one positive and one negative half, ending at x
4. DGraph D: displacement against distance, full sine wave starting at maximum displacement, ending at x

As printed in the paper