Visible light (physics only) — AQA GCSE Physics
Test yourself on Visible light (physics only) with AQA GCSE practice questions.
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Visible light (physics only) explained
Questions on this content chain several steps together, so work through them in order: what light leaves the source, what the filter transmits and absorbs, what the surface reflects and absorbs, and what finally reaches the eye.
Read the full explanation
Colourless glass transmits all of the white light, so nothing changes. Blue glass transmits only the blue and absorbs the other colours, so anything seen through it is lit by blue light alone. A red book viewed through a blue filter then looks black, because the only light reaching it is blue and the red surface absorbs blue. Each transmitted colour and each absorbed colour is credited separately, so name both rather than describing the result as the light changing colour.
Your focus
- Trace a beam of white light through a named filter to an object and predict the colour seen.
- Explain in terms of transmission and absorption what a coloured filter does to white light.
- Account for the colour of an opaque object under a stated illumination using reflection and absorption.
Visible light (physics only) exam tips
Marking Points
- one mark for stating that colourless glass transmits the white light unchanged
- one mark for stating that blue glass transmits only the blue light
- one mark for stating that all the other colours, wavelengths or frequencies are absorbed
- one mark for chaining the filter and the surface together to predict the final appearance of an object
Examiner Tips
- 💡Work through source, filter, object, eye in that order and write one sentence for each stage.
- 💡Two answer boxes mean two separate answers; do not use one to cover both materials.
- 💡Stick to the vocabulary transmitted, absorbed and reflected throughout.
Common Mistakes
- describing only the colour that gets through and never naming what is absorbed
- saying the filter reflects the missing colours back towards the source
- treating an object's colour as fixed, independent of the light actually reaching it
- writing that the light 'turns blue' as it passes through the glass