A light ray can undergo total internal reflection under specific conditions.
Explain what is meant by the term critical angle.
State two conditions required for total internal reflection to occur.
The diagram shows a light ray entering a semicircular glass block and travelling towards the centre point O.
The angle of incidence iii is 48∘48^\circ48∘. The critical angle of the glass is 39∘39^\circ39∘.
Which path does the ray take after reaching point O?
State the equation linking critical angle and refractive index.
Calculate the refractive index of the glass.
