Figure below show two rays A and B travelling from water to air. If the critical angle for water- air surface is 48°, complete the ray diagram showing the refracted rays for each. State conditions when the ray will suffer total internal reflection.
Figure below show two rays A and B travelling from water to air. If the critical angle for water- air surface is 48°, complete the ray diagram showing the refracted rays for each. State conditions when the ray will suffer total internal reflection.

Solution ;

There are two prerequisites for total introspective reflection:

(i) Light must pass through a denser media before reaching a rarer medium.

(ii) The incidence angle must be larger than or equal to the critical angle.

The angle of incidence in this example is I > 48 degrees.