Question

An air bubble in a glass slab (μ = 1.5) is 5 cm deep when viewed from one face and 2 cm deep when viewed from the opposite face. The thickness of the slab is(a) 7.5 cm(b) 10.5 cm(c) 7 cm(d) 10 cm

Answer 1

Answer:

D) 10cm

Explanation:

Relation between real depth and apparent depth -

ni/d = nr/d'

wherein

ni = Refractive index of medium of incident.

nr= Refractive index of medium of refraction.

d = distance of object.

d' = apparent  depth

Apparent depth = 5cm  from one side  

Thus real depth= 1.5x5=7.5 cm  

Apparent depth = 2 cm from other side  

Thus real depth from other side = 2 x1.5cm=2.5

Thus, the thickness of slab = 7.5cm+2.5cm = 10cm