A sound wave travels through air at a speed of $320\,\text{m s}^{-1}$. The graph shows how the displacement of an air particle caused by this wave changes with time. Which statement about the sound wave is correct?
- AThe frequency of the wave is $500\,\text{Hz}$.
- BThe graph shows that sound is a transverse wave.
- CThe intensity of the wave will be doubled if its amplitude is increased to $0.4\,\text{mm}$.
- DThe wavelength of the sound wave is $1.28\,\text{m}$.