1. The problem statement, all variables and given/known data A ray of pure yellow light reaches the surface of a pond at an angle of incidence of 60°. What angle does it make with the normal inside the water? Speed of light in air = 300,000,000 m/s Speed of light in water = 225,000,000 m/s So the Refractive index μ = 1.33 2. Relevant equations μ = angle of incidence / angle of refraction 3. The attempt at a solution μ = sin i / sin r 1.33 = 60° / sin r sin r = 60° / 1.33 So the angle of refraction equals 45.11°. Is this correct? I believe this is the correct way to work it out, yet when I check the answer online using various calculators the answer comes up as 40.62°. Am I doing something wrong?