Question

Write an activity to explain the phenomenon of refraction of light through a triangular glass prism?
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Answer 1

• If we will take a glass prism, you can see that it has 2 triangular bases and three rectangular lateral surfaces, inclined at an angle. This angle is called the angle of the prism.

• Let’s look at a top view of a triangular prism with a ray of light entering it.

• Refraction Of Light Through A Glass Prism.

• In the figure above, A is the angle of the prism.

• In the figure above, A is the angle of the prism.As per Snell’s law, light travelling from a rarer medium to a denser medium bends towards the normal, and vice versa.

• Glass is denser than air, and thus, when a ray of light falls on the surface of the prism, it bends towards the normal.

• According to the diagram, ray PE falls on the surface of the prism and bends towards the normal NE.

• Then, while moving from the glass to air, the emergent ray FS bends away from the normal.

• ∠HDS is the angle of deviation which tells us how much the emergent ray has deviated from the incident ray.

• When the angle of incidence is equal to the angle of emergence, the angle of deviation is minimum.

• According to the figure, ∠PEN = ∠MES and ∠HDS is thus the angle of minimum deviation. The refracted ray EF is parallel to side BC in this case.

This is how a ray of white light scatters into 7 colours when it passes through a prism. The different colours of light wave experience a different degree of deviation and thus white light splits into its components when it is subjected to refraction.