[Jamie1916]

I don't know if this should be in the Chemistry forum but I'm doing a chemistry degree so I'll put it here, it seems like a more physics type question to me though!

We have this question that state;

Observing screen placed away from pin hole = 1.25m
Second bright light ring 5cm from central spot
Wavelength of light = 630nm

Calculate the size of the slit (Single hole remember!)

I've been struggling to find anything online related to single hole calculations, nothing in my notes either. I've found a section in a physics book I have however the only example they show is one to find the positions of the first dark fringes (this shows all the working and explains it), however when it gets to the determining the width of the first-order bright fringe it just has an answer and nothing else! Not much use!

I'm completely lost with it and the only thing I have found is example 3 on the following website

http://www.studyphysics.ca/newnotes/20/unit04_light/chp1719_light/lesson58.htm

I still can't get it to work though when I try and use that system!

Can anyone help?!