6. The figure below shows what it is known as an anamorphic prism pair. These are oriented so that the beam enters each prism at the same angle of incidence, and in the case shown leave perpendicular t the exit surfaces. If the refractive index of the glass is n show that the beam width in the plane of the diagram is expanded by a factor C = = [n = [n - sin]/[n cos i] a a 1 b C