A microscope is focused on a needle lying is am empty tank. Now, the tank is filled with benzene to a height 120 mm. The microscope is moved 40mm to focus the needle again the refractive index of benzene is:
A) \[1.5\]
B) \[2.5\]
C) \[3.0\]
D) \[4.5\]
Correct Answer:
A
Solution :
As \[\mu =\frac{\text{Real depth}}{\text{Apparent depth}}=\frac{120}{120-40}=1.5\]