# Homework Help: Weird Superposition Question

1. Nov 10, 2005

### foxtrot2

Hello! I'm new here, and this is my first post. I hope I have not breached any rules, but here's a rather strange (in my limited intelligence) question I encountered. I shall try to explain the question because I am unable to reproduce the diagram.

Two identical narrow slits S1 and S2 are illuminated by light of wavelength (lambda) from a point source P.

[diagram = So, P (on the left) is connected to the line marked S1 and S2 by two lines l1 and l2. l1 is longer than l2. A point Q on the right of the line S1S2 is connected to S1 by l3 and S2 by l4, l3being longer than l4]

The light is allowed to fall on a screen (at Q), and if m is a positive integer, the condition for destructive interference at Q is that...

Thanks for the help!

EDIT: Crap, I just realised this is in the wrong thread... I really apologise for bungling up my first post and the inconvenience I have caused.

Last edited: Nov 10, 2005
2. Nov 10, 2005

### Kazza_765

Show us what you have tried already. Remember, for destructive interference the path difference must be equal to 1/2 or 3/2 or 5/2 or 7/2 etc wavelengths.