What is the critical angle θcrit for light propagating from a material with index of refraction of 1.50 to a material with index of refraction of 1.00? express your answer in radians?

Answer: As the ray is travelling from denser to rarer medium, Therefore sin i / sin r = 1 / RI = Sin 90 / Sin i = RI (Reciprocal) (Sin 90 because for critical angle Sin r = 90) = 1 / Sin i = 3/2 = Sin i = 0.667 Now converting this value to degrees It becomes Sin 42. Therefore the critical angle is 42. 42 degrees = 0.733038286 radians