A ray of light traveling from water (denser) into air (rarer) grazes the interface separating the two media. The angle of incidence in the water is called the: MCQ with Answer and Explanation

When light travels from an optically denser medium to a rarer medium, it bends away from the normal. As the angle of incidence increases, the angle of refraction also increases. The specific angle of incidence for which the refracted ray grazes the surface (meaning the angle of refraction is exactly 90 degrees) is defined as the critical angle.