Question

When light enters from one medium into another, we say refraction takes place. Light bends on undergoing refraction, when light enters from rarer medium into denser medium, it will bend towards the normal. Similarly, when light gets into rarer medium from a denser medium,it will bend away from the normal. 

(i) State the laws of Refraction.  

(ii) 'Due to refraction, the original depth of a tank cannot be known'. Give any three examples of effects of refraction in support of the statement.

Answer 1

(i) Laws of refraction :

(a) The incident ray, the normal and the refracted ray, all lie in the same plane.

(b) The ratio of sine of the angle of incidence and sine of the angle of refraction is constant. Which is called the refractive index.

(ii) Three examples of refraction :

(a) A coin placed at the bottom of a glass tumbler appears to be raised.

(b) Pencil immersed in water appears to be bent when viewed from sides.

(c) Lemon kept in water bow4 appears to be larger.