(a)[1]
State how sound is different from ultrasound.
(b(i))[3]
Explain what a wave means and describe how a longitudinal wave is different from a transverse wave.
(b(ii).1)[1]
On Fig. 9.1, place two points at the centres of two different rarefactions and label each point R.
(b(ii).2)[1]
On Fig. 9.1, draw a double-headed arrow to show a distance equal to one wavelength of the wave.
(b(ii).3)[2]
Measure the length of the arrow drawn on Fig. 9.1 and use it to determine the speed of the wave in oil.
(c(i))[1]
State what happens to the speed of the sound wave as it enters air.
(c(ii))[3]
On Fig. 9.2, draw the sections of these compressions that are in the air.
(d)[3]
Describe, in outline, how ultrasound is used in cleaning.