(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

http://img225.imageshack.us/img225/3118/photo1587hx4.jpg [Broken]

This #74 is on the SAT Practice Subject Test in Physics, which is also the Physics test administered in January 2003.

2. Relevant equations

I don't even know how to begin this problem.

3. The attempt at a solution

I know Young's double-slit equation: nλL=dx

But I don't know any equation for the 'x' and 'y' in the diagram, the distance from the actual slits to the band other than the Pythagorean theorem.

I tried solving with those, and I get a difference, but it's not one of the provided answers.

In my attempt I called the slits A (top) and B (bottom) (since 'x' is the fringe distance), and the distances (x and y in the diagram) Za and Zb.

The system of equations I tried to manipulate was:

Za^{2}=L^{2}+ (d/2 - x)^{2}

Zb^{2}=L^{2}+ (d/2 + x)^{2}

nλL=dx

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# Homework Help: Distance between each double-slit and the light band.

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