Question

A 45945990 prism is immersed in water. A ray of light is incident normally on one of its shorter faces. What is the minimum index of refraction that the prism must have if this ray is to be totally reflected within the glass at the long face of the prism

Answer 1

Step-by-step explanation:

Angle of incidence at the longer face = 45⁰ ( see the figure in the attached file )

For total reflection from longer face

i = C where C is critical angle .

And relation between critical angle and refractive index is as follows .

μ = 1 / sinC

= 1 / sin45

= √2

= 1.414 .