A conservator investigates an opaque pigment sample. The sample can reflect one or more of red, green and blue light and absorbs any of these colours that it does not reflect.
In each test, a lamp produces only the colours shown. Light reflected from the same unchanged area of the sample passes through a filter to a detector. Each filter transmits only the colours shown and absorbs the other colours. The detector identifies every colour of light that reaches it. If one colour is listed as the result, no other colour reached the detector.
| Test | Colours produced by lamp | Colours transmitted by filter | Colours detected |
|---|---|---|---|
| 1 | red and green | red and green | red |
| 2 | green and blue | green and blue | blue |
| 3 | red, green and blue | green and blue | not recorded |
Explain which colour or colours, if any, the detector would identify in test 3.
93 exam-style questions on Edexcel GCSE Physics 5.1 Reflection, refraction and lenses, covering 5.1.1 Reflection, refraction and total internal reflection, 5.1.2 Specular and diffuse reflection, 5.1.3 Colour of light: absorption and filters, 5.1.4 Lenses: power, focal length and shape, 5.1.5 Ray diagrams for converging and diverging lenses, and 5.1.6 Real and virtual images. Each one has a worked solution and a mark scheme showing where the marks go.