Question

A
(a) Define critical angle.
(b) A ray of light passes
through a right-angled
prism as shown in
the adjoining figure.
State the angles of
incidence at the faces AC
and BC.
[2004]
​

Answer 1

Answer:

Critical angle is angle of incidence of a ray of light, moving from denser medium to rarer medium, such that the angle of refraction becomes 90°.

hope it helps.....

Answer 2

(a) When the angle of incidence in water reaches a certain critical value, the refracted ray lies along the boundary, having an angle of refraction of 90-degrees. This angle of incidence is known as the critical angle.

Or

The critical angle is the angle of incidence where the angle of refraction is 90°. The light must travel from an optically more dense medium to an optically less dense medium.

(b) To find

angle of incident foces AC & BC

The light ray incident on AC

i=45

o

& Light fall normally on BC (Perpendicularly)

i.e angle of incident is zero for BC

i=0

Hope this will help you

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