A Boy Observes A Piece Of Stone At The Bottom Of A River 6.0m Deep. If He Looks From The Surface Of The River. What Is The Apparent Distance Of The Stone From Him? [Refractive Index Of Water = 4/3]

A. 8.0m
B. 5.5m
C. 5.0m
D. 4.5m

Correct Answer:

Option D = 4.5m

Explanation

Refractive Index = Real Depth/App. Depth
4/3 = 6/app. depth
App Depth = (3 x 6)/4 = 4.5m

A boy observes a piece of stone at the bottom of a river 6.0m deep. If he looks from the surface of the river. What is the apparent distance of the stone from him? [Refractive Index of Water = 4/3]