(a)[2]
State what is meant by longitudinal.
(b(i))[2]
Fig. 5.1 shows an ultrasound cleaner in use for cleaning jewellery. The jewellery is placed in the cleaning fluid, and ultrasound waves with frequency $42\,000\,\text{Hz}$ are generated in the fluid. The speed of ultrasound in the fluid is $1500\,\text{m s}^{-1}$. Calculate the wavelength of the ultrasound in the fluid.
(b(ii))[2]
Describe how the ultrasound cleans the jewellery.