Question

Critical angle of water is 48°. What do you understand by the statement?

Answer 1

It means that when a ray travels from water towards air and strikes the water–air boundary at an angle of incidence of 48° in water, the refracted ray travels along the surface (the angle of refraction is 90°). Thus, 48° is the critical angle for water. If the angle of incidence is greater than 48°, total internal reflection occurs.