A coin place below a rectangular glass block of thickness 9cm and refractive index 1.5 is viewed vertically above the block. The apparent displacement of the coin is?

A. 3 cm
B. 5 cm
C. 6 cm
D. 8 cm

Correct Answer:

Option A – 3 cm

Explanation

Real depth = thickness of the glass block = 9cm.
Refractive index of the glass material = 1.5
But Refractive index = Real depth/Apparent depth
=> 1.5 = 9/Apparent depth
therefore Apparent depth = 9/1.5 = 6cm.
therefore Apparent displacement of the Coin = 9.6
= 3cm