GCSE questions on refraction

Q5. Some students used water waves in a ripple tank to model the behaviour of light waves.

The diagram shows what happens to the wave fronts as they pass the boundary between deep water and shallower water.

(a) Explain why refraction happens at the boundary between the deep water and shallower water.

[3 marks]

(b) The next diagram shows the wavefronts travelling parallel to the boundary between deep water and shallower water. Explain why the wavefronts do not refract at the boundary.

[2 marks]

(Total 5 marks)