Q.46

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Found in: Page 992

### Physics for Scientists and Engineers: A Strategic Approach with Modern Physics

Book edition 4th
Author(s) Randall D. Knight
Pages 1240 pages
ISBN 9780133942651

# A microscope is focused on a black dot. When a -cm-thick piece of plastic is placed over the dot, the microscope objective has to be raised cm to bring the dot back into focus. What is the index of refraction of the plastic?

The index of refraction of the plastic is

See the step by step solution

## Step 1: Given information

We are given that the thickness of plastic piece is

and the microscope objective has to be raised to bring the dot back into focus. We have to find refractive index of plastic.

## Step 2: Simplify

As we know,

Where,

refractive index of medium of object

refractive index of medium of observer

distance of object

distance of image

Now, according to question

The distance of black dot of plastic piece (object) is

The distance of image is

Refractive index of air is