Question A laser beam travels from air into a symmetrical prism at right angles close to its upper edge. The refractive index of the prism material n = 1.4 and its angle is 30 degrees. i) Calculate the critical angle for the prism-air interface. Possible Answer: Critical angle = arcsine(1/n) arcsine(1/1.4) = 45.585 degrees ii) After passing through the prism, what angle does the beam make with the incident ray? Possible Answer: Sine Angle = (n of prism)(Sine30)/n of air = ((1.4)(Sin30))/1.0 Sine Angle = 0.7 Angle = 44.427 degrees Are these correct?