Refraction
3 marks · NormalA ray of light passes from air into a block of glass. The diagram below shows the path of the ray.
On the diagram, clearly label the angle of incidence and the angle of refraction.
State which of the two angles (angle of incidence or angle of refraction) is larger and explain why.
Work this out on paper, then compare with the answer and worked solution below. With a free account you can submit written answers for marking.
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(a) — · must show Correctly placed and labelled angle of incidence (between incident ray and normal), Correctly placed and labelled angle of refraction (between refracted ray and normal)
(b) The angle of incidence is larger. This is because light travels slower in glass than in air, causing the ray to bend towards the normal and reduce the angle. · must show Statement that angle of incidence is larger, Explanation related to change of speed or bending towards normal
Show mark scheme and worked solution
Marking points
B1 (a) · 1 mark · Correct position and label for angle of incidence (between incident ray and normal on air side)
B1 (a) · 1 mark · Correct position and label for angle of refraction (between refracted ray and normal on glass side)
B1 (b) · 1 mark · States angle of incidence is larger and gives reason (light slows in glass or bends towards normal)
Worked solution
a) Draw and label the angle between the incident ray and the normal as the angle of incidence. Draw and label the angle between the refracted ray and the normal as the angle of refraction. b) The angle of incidence is larger because light slows down in glass and bends towards the normal, reducing the refracted angle.