Refractive index is the ration of sin i to sin r where i is the incident angle and r is the refraction angle. Therefore, refractive index = sin 79.5 / sin 39.6 = 1.542 The refractive index may be given by the ratio of refractive index of medium 2 to refractive index of medium 1. Therefore, 1.542 = n/1.0003 n = 1.5425 ≈ 1.54 Medium 2 is sodium chloride, refractive index of 1.54
