Question

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Answer 1

option (d)

90 degrees

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Answer 2

Answer:

42°

Explanation:

When a right ray passes from a denser medium to a rarer medium, at a certain angle of incidence; i = C, the angle of refraction becomes 90°, ie., at i = C, r = 90°. C is called the critical angle.

Critical angle is the angle of incidence in the denser medium corresponding to which the angle or refraction in the rarer medium is 90°.