'Critical angle of water is 48'Explain the meaning of the statement.

Critical angle is the angle of incidence in a denser medium for which angle of refraction in the rarer medium is 90°. Hence, the angle more than critical angle causes ray to reflect back in the incident denser medium.

Critical angle of water is 48 degree means, at angle 48 degree the angle of refraction is 90 degree i.e. the refracted ray moves along the interface of the media. Beyond this angle the ray reflect back or undergoes in total internal reflection.