Page 1 - Lesson note refraction through prism

SAI INTERNATIONAL SCHOOL
PHYSICS
CLASS X
Chapter: LIGHT(Human eye and the colourful world)
MODULE-37

LESSON NOTES: refraction through prism,dispersion through prism

A glass prism is a transparent object having two triangular ends and three
rectangular sides. The refraction of light in glass prism is different from a glass slab.
This is because in glass prism, the incident ray of light is not parallel to emergent ray
of light.

When a ray of light enters the glass prism it gets deviated two times. First when it
enters the glass prism and second when it comes out of the prism. This is because
the refracting surfaces of the prism are not parallel to each other. Also, when the ray
of light passes through the prism it bends towards its base.

When a ray of light passes through a glass prism, refraction (or bending) of light
occurs both, when it enters the prism as well as when it leaves the prism. Since
the refracting surfaces (PQ and PR) of the prism are not parallel, therefore, the
emergent ray and incident ray are not parallel to one another.

An oblique ray of light suffers two refractions on passing through a
triangular prism and hence, deviates through a certain angle from its original path.
The angle between the incident ray and emergent ray is called the angle of
deviation.

Factors affecting angle of deviation of prism
Following are the factors on which the angle of deviation depend on:

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