The density of air is 1.3 kg/m3 and the speed of sound in air is 340 m/s. The pressure amplitude of a tone with angular frequency 900 rad/s is 0.30 Pa. What is the displacement amplitude?

9.0 × 10-7 m
7.5 × 10-7 m
6.0 × 10-7 m
4.5 × 10-7 m