# Thread: Impact of white light source on fringe pattern

1. ## Impact of white light source on fringe pattern

Hi
A little help will be appreciated

(a)Double slit interference fringes are observed using light of wavelength 590nm abd a pair of double slits of spcing o.50mm. The fringes are observed on a screen at a distance of 0.90m from the double slits. Calculate the fringe seperation of these fringes.

(b)Describe and explain the fringe pattern that would be observed if the light source were replaced by a white light source

SOLUTION
I was able to do (a)

With (b) I surmised that fringe patterns would increase. White light contains a wide range of wavelengths. So, according to
W= (Wavelength x D)/s

The fringe pattern is proportional to the wavelength.

2. Right, white light contains a variety of wavelengths, and each wavelength will be diffracted by a different amount, so that you have different patterns. And since the wavelength is what determines the colour of the light, you'll have patterns of all sorts of colour!

3. You are a star! Apologies for all the questions. I am full time worker battling Maths, Physics AND Further Maths A levels!

Cheers!!

4. Oh, you're in your first year of A level Physics is seems. I just finished my second year. I have Chemistry exam this Friday (the last exam).