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Q. 35

Expert-verified
Found in: Page 956

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

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

# Light from a helium-neon laser is used to illuminate two narrow slits. The interference pattern is observed on a screen behind the slits. Twelve bright fringes are seen, spanning a distance of . What is the spacing (in mm) between the slits?

The Spacing distance between the two slits is.

See the step by step solution

## Step1: Helium-neon laser

Helium-neon (He-Ne) lasers are often used for interferometry because they are inexpensive and produce a consistent, visible output. They generally work at a wavelength of , however customized versions with useable outputs at other visible and infrared wavelengths are also available.

## Step2:

The distance between two adjacent fringes is calculated as follows:

is the distance between two subsequent slits, and is the distance between two successive slits.

We have bright fringes in this problem, which means there are spaces between them. If , the distance between successive brilliant fringes is calculated as follows:

When we combine the two equations for , we get

This results in,

We get numerical values and return them.