In the diagram shown ray of light is incident on the first medium boundary at angle 30⁰ the medium has refractive index 2.

The second layer has refractive index $\raisebox{1ex}{$\mu $}\!\left/ \!\raisebox{-1ex}{$2$}\right.$.  A graph is given between deviation and refractive index '$\mu$'.  The deviation is measured by considering the final emergent ray and the incident ray