Question: Two right–angled 300–600–900 glass prisms are cemented along the hy...

Question

Two right–angled 30⁰–60⁰–90⁰ glass prisms are cemented along the hypotenuse by Canada balsam, where µ = 1.632. What should be the minimum refractive index of the material of the prisms so that the ray passing through one end may be totally reflected?

Answer 1

Solution

The angle of incidence on the layer is 60⁰, So the ray is totally reflected if 60ŗ ³ C, where C is the critical angle for glass balsam surface.

sin 60⁰ ³ sin C or $\frac { \sqrt { 3 } } { 2 }$ ³ sin C

$\frac { 1.632 } { \mu }$

µ ³ 1.88

µ_min = 1.88

Question: Two right–angled 30<sup>0</sup>–60<sup>0</sup>–90<sup>0</sup> glass prisms are cemented along the hy...

Solution