Question

If the angle of incidence is equal to critical angle, then the angle of refraction is
a) 0°
b) 20°
c) 90°
d) 180°
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Answer 1

Explanation:

90°

When the angle of incidence is equal to the critical angle, the angle of refraction is equal to 90°. If the angle of incidence is bigger than this critical angle, the refracted ray will not emerge from the medium, but will be reflected back into the medium. This is called total internal reflection.