Question

A Young's interference experiment is performed with blue-green argon laser light. The separation between the slits is 0.500 mm, and the screen is located 3.30 m from the slits. The first bright fringe is located 3.40 mm from the center of the interference pattern. What is the wavelengtl of the argon laser light?

Answer 1

The wavelength of the argon laser light is 515 nm

Step-by-step explanation:

For bright spot,

The relation between the distance of the slits and the angle through which it is passed is:

dsinθ=nλ

where,

n can be any integer

d is the distance between the two slits

λ is the wavelength of light.

Since for the first bright fringe, n=1

The experiment sceneerio can be drawn with the help of an image shown below.

So,

Using Pythagoras theorem for ΔABC

AB² + BC² = AC²

Thus,

AC² = (3300)² + (3.40)²

AC = 3300.0018 mm

sinθ = 3.40/3300.0018 = 0.001030

Applying the values in the formula as:

0.5 mm×0.001030=(1)λ

So,

The wavelength = 0.000515 mm

Also, 1 mm = 10⁶ nm

So, wavelength = 515 nm