A light beam is traveling through an unknown substance. When it strikes a boundary between that substance and the air Mair 1), the angle of reflection is 27.0\deg and the angle of refraction is 43.0\deg . What is the index of refraction n of the substance? n= -0.8697 Incorrect light beam is traveling through an unknown substance. When it strikes a boundary between that substance and the air t_air ≈ 1 ), the angle of reflection is 27.0^∘ and the angle of refraction is 43.0^∘. What is the index of refraction n of the substance?