00:01
In this problem, we have a double slit experiment, so we have two slits separated by a distance d, because the space right here between the two black lines, and some distance l away is a screen.
00:17
And on this screen, we're going to see a fringe pattern with bright spots and dark spots.
00:25
All right, so the bright spots are these circles and the dark spots are the spaces between them.
00:29
And the relationship for the double slip pattern for the bright spots is that if this is the angle theta to some bright spot, here it's to the second one, but it could be to any of them, is given that by d sine theta sub n, where sub n means the nth bright spot equals n times lambda.
00:56
So n is an integer here.
00:58
And lambda is the wavelength of the light shining through here.
01:02
Now in this problem they're giving us two different lights being shine through the same setup and they want to know what is the distance between the two third bright fringes.
01:14
So this would be the third bright fringe over here.
01:17
I'll do it on the bottom so that we don't have the drawings right on top of each other.
01:20
So here's a third bright fringe.
01:24
So this would be theta 3, right? and the distance to theta 3 i'm going to call x...