Physics (AS & A Level) · May / June 2016 · Paper 13 · Question 25

The intensity I of sound is inversely proportional to the square of the distance x from the source of the sound. This can be represented as I ∝ 1/x². Air molecules at point P, a distance r from the source S, oscillate with amplitude 8.0 µm. Point Q is situated a distance 2r from S. What is the amplitude of oscillation of air molecules at Q?

1. A1.4 µm
2. B2.0 µm
3. C2.8 µm
4. D4.0 µm

As printed in the paper