A torch gives out white light. An astronomer covers the torch with a red filter and uses it to read a star chart printed on white paper.
State what happens to the red light from the torch when it reaches the filter.
State what happens to most of the other visible colours at the filter.
The names of the stars can be printed in red ink or in blue ink.
Which colour of ink makes the names easier to read in the light from this torch? Give a reason for your answer.
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.