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
A) 2.0
B) 2.5
C) 1.6
D) 1.5
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) \[\mu =\frac{15-6\mu }{4}\Rightarrow \mu =1.5\]