Question

The refractive index of glass is 1.54 what is the critical angle?

Answer 1

Answer:

critical angle for glass is 42°

Explanation:

nothing much to explain

Answer 2

Answer:

1/sinc = 1.54

sin c = 0.6494

c = sin⁻¹(0.6494)

c = 40.49 degrees

Explanation:

Refractive Index = sin i/sin r = 1/sin c

(Why is it 1/sin C?

When light exits a denser medium with a certain angle called 'critcal angle - c', it forms a 90 degree angle with the boundary between the media. Therefore:

sin i = sin 90 = 1

sin r = sin c              (c = critical angle)

Refer to part b) of the diagram to understand better!