Calculate how many crests are formed in $1.5\,\text{s}$.
Wave height is taken relative to the level of the undisturbed water surface. At time $t=0$, the wave height at one point is $0$. On Fig. 8.2, draw a graph to show how the wave height at this point changes with time.
The wave frequency is increased. Describe how the apparatus shown in Fig. 8.1 should be changed so that the frequency of the wave increases.
State what happens to the speed and wavelength when the frequency increases.
The apparatus shown in Fig. 8.1 can be used to demonstrate refraction. State the extra apparatus required to demonstrate refraction.
Draw on Fig. 8.3 to show the refraction of the water wave. Label a boundary where refraction takes place.
Calculate the time taken for data to travel from A to B using microwaves.
State one feature that infrared waves and microwaves have in common.
Suggest one further advantage of using optical fibres to connect stations A and B directly.