## Book: HC Verma - Concepts of Physics Part 1

### Chapter: 18. Geometrical Optics

#### Subject: Physics - Class 11th

##### Q. No. 16 of Exercises

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16
##### A small piece of wood is floating on the surface of a 2.5 m deep lake. Where does the shadow form on the bottom when the sun is just setting? Refractive index of water = 4/3.

2.83 m shifted from the position directly below the piece of the wood.

the wooden piece is floating on the surface of lake.

Hence, height of the lake= 2.5m

When sun is setting, then the rays of the sun will become approximately parallel to the surface of lake as shown in the figure. Hence, the sun rays will become perpendicular to the normal of the surface of the lake.

θ is approximately = 90°

using Snell’s law

From the figure shown

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