Question 11
FA periscope uses two glass prisms to change the direction of light.
The Figure shows a ray of light passing through one of the prisms. The critical angle of the glass is 42∘42^{\circ}42∘.
Figure
a.[1]
Describe what happens to the direction of the ray as it enters the prism.
b.[1]
Determine the angle of incidence at the long face of the prism.
c.[2]
Explain why the ray is totally internally reflected at the long face.
d.[1]
Determine the total change in direction of the ray as it passes through the prism.
e.[2]
A prism of the same shape is made from a plastic with a critical angle of 48∘48^{\circ}48∘.
Explain why this plastic prism would not be suitable for the periscope.
5.1 Reflection, refraction and lenses Questions
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.