Question

The angle of incidence of a ray for which the angle of refraction is ${90}^{\circ }$ is called

• A. Scattering angle
• B. Reflex angle
• C. Critical angle
• D. Optical angle

Answer 1

The correct option is C Critical angle

The angle of incidence of a ray for which the angle of refraction is ${90}^{\circ }$ is called critical angle.
When the angle of incidence of a ray is greater than the critical angle, the refracted ray is in the same medium, i.e., the light is totally reflected in the same medium. This is known as total internal reflection.