Optics Question 782

Question: A transparent cube of 15 cm edge contains a small air bubble. Its apparent depth when viewed through one face is 6 cm and when viewed through the opposite face is 4 cm. Then the refractive index of the material of the cube is

[CPMT 2004; MP PMT 2005]

Options:

A) 2.0

B) 2.5

C) 1.6

D) 1.5

Show Answer

Answer:

Correct Answer: D

Solution:

When viewed from face (1) $ \mu =\frac{u}{v}=\frac{x}{v} $

$ =\frac{x}{6} $ …..(i)

Now when viewed from face (2) $ \mu =\frac{15-x}{v}=\frac{15-x}{4} $ …..(ii)

From equation (i) and (ii) $ \mu =\frac{15-6\mu }{4} $

$ \Rightarrow \mu =1.5 $ .



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