(a(i))[1]
On Fig. 6.1, put a cross at the centre of a compression and label it C.
(a(ii))[1]
On Fig. 6.1, put a cross at the centre of a rarefaction and label it R.
(a(iii))[1]
On Fig. 6.1, draw a double-headed arrow to show a distance of $0.90\,\text{m}$.
(b)[2]
Calculate the wave’s speed.
(c)[1]
Suggest a medium through which the sound wave is travelling and state your reasoning.
(d(i))[1]
Another type of wave made up of compressions and rarefactions is ultrasound. State one other similarity between sound of frequency $750\,\text{Hz}$ and ultrasound.
(d(ii))[1]
State one way in which sound of frequency $750\,\text{Hz}$ is different from ultrasound.