Question

Identify the condition under which total Internal reflection occurs.

• A. when light passes from air into water.
• B. when light refracts as it exits glass into air
• C. when light reflects off of a mirror.
• D. when light passing through glass is reflected inside the glass.
• E. when the angle of incidence is less than the critical angle.

Answer 1

Answer: (D)

when light passing through glass is reflected inside the glass.

For total internal reflection to occur, the angle of refraction should be greater than ${90}^{\circ }$.

Hence in ${\mu }_{1}sini={\mu }_{2}sinr$

$⟹{\mu }_1>{\mu }_2$

Hence for total internal reflection to occur, light must be inside the optically denser medium.