Question

Total internal reflection of light can occur when light travels from __________.

• A. air to glass
• B. vacuum to air
• C. air to water
• D. water to air

Answer 1

The correct option is D

water to air

When light travels from denser to rarer medium, it bends away from the normal. When the angle of incidence becomes greater than the critical angle (angle of incidence for which angle of refraction is ${90}^{\circ }$), light gets reflected in the same medium without undergoing refraction and this phenomenon is known as total internal reflection. Here, water is denser than air. Therefore, total internal reflection takes place when light travels from water to air with angle of incidence greater than critical angle.