What is the critical angle for a light ray traveling from a denser medium of refractive index 2 into a rarer medium of refractive index 1?

💡 Solution & Explanation

The critical angle is calculated using Snell law where the sine of the critical angle equals the ratio of the refractive index of the rarer medium to that of the denser medium. For refractive indices of 1 and 2, the sine equals 0.5, which corresponds to an angle of thirty degrees. Exceeding this angle results in total internal reflection.