A ray of light hits a plane mirror at an angle of 30° to the normal. State the angle of reflection and name the law used.
[2 marks]
Total for this question: 2
Physics required practicals
Reflection and refraction of light
AQA 4.6 · RP9 (physics only)
GCSE Physics (8463) · Required practical 9 — method, variables, the marks examiners report students losing.
(physics only) means this content belongs to AQA GCSE Physics (8463), the separate-science qualification, but not AQA Combined Science: Trilogy (8464). It is not an exam tier: (HT only) separately marks Higher-tier content.
Board and spec code confirmed against AQA 8463 · registry checked 2026-07-17How this checking works
Investigate the reflection of light by different types of surface and the refraction of light as it passes into different substances.
Apparatus
- Ray box with a single slit, and a power supply
- Rectangular glass or perspex block (and other transparent materials)
- Plane mirror and surfaces of different roughness for reflection
- Protractor, 30 cm ruler and a sharp pencil
- Plain paper on a soft board
Method
- 1Reflection: draw a straight line for the surface and a normal at 90° to it; shine a single ray at the point where the normal meets the surface.
- 2Mark the incident and reflected rays with crosses, remove the mirror and draw the rays; measure the angle of incidence and angle of reflection from the normal.
- 3Refraction: place the glass block on the paper and draw around it; shine a ray into one side at an angle and mark where it enters and leaves.
- 4Remove the block, join the marks to show the ray inside the glass, and draw the normal at the point where the ray enters.
- 5Measure the angle of incidence and the angle of refraction from the normal; repeat for different angles or different materials.
Variables
Independent
The type of surface (reflection) or the substance / angle of incidence (refraction)
Dependent
The angle of reflection, or the angle of refraction
Control
- A single narrow ray from the same ray box
- The angle of incidence when comparing different materials
- The same block position and paper
Results & processing
- For reflection, the angle of incidence equals the angle of reflection (both measured from the normal).
- Going from air into glass (a more dense medium) the ray bends towards the normal, so the angle of refraction is smaller than the angle of incidence; leaving the glass it bends away from the normal.
Where students lose marks
Measuring angles from the surface instead of the normal.
Fix: Always measure the angle of incidence, reflection and refraction from the normal (the line at 90° to the surface).
Thick, fuzzy ray lines.
Fix: Use a single narrow ray and a sharp pencil, and mark each ray with two crosses far apart before drawing it.
Drawing round the block inaccurately.
Fix: Draw round the block carefully and put it back in exactly the same place if you need to check a ray.
Improve the method
- Use a sharp pencil and a single thin ray to reduce uncertainty.
- Mark each ray with two crosses set well apart, then draw the line through them.
- Repeat for several angles and look for the pattern.
Try it — exam-style
Easy
ORIGINAL
Medium
ORIGINAL
Describe how the direction of a light ray changes as it passes from air into a glass block and then back out into the air.
[2 marks]
Total for this question: 2
Questions are written in the style of past AQA papers — never copied from them.
Drill it properly
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