With appropriate ray diagram explain Refraction of light through a Rectangular Glass Slab.

Question

(a) With appropriate ray diagram explain Refraction of light through a Rectangular Glass Slab.

(b) A concave lens of focal length 15 cm forms an image 10 cm the lens. How far is the object placed from the lens? Draw the ray diagram.

Answer 1

Refraction of light is the bending of light as it goes from one medium to another. If it goes from rarer to denser medium, it bends towards the normal, while it goes from denser to rarer, it bends away from normal. If it is normally incident, it does not bend, but speed changes. 

f -20

v = -10

1/v -1/u = 1/f

-1/10 -1/u =-1/20

1/u = 1/10 +1/20

u =-20

∴ Object is placed at the focus.