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

A point source of light (λ = 589 nm) is placed 0.4 mm above the surface of a glass mirror. Interference fringes are observed on a screen 6m away, and the interference is coming from light reflecting off the mirror and light coming directly from the source. Find the spacing of the fringes

2. Relevant equations

reflection from the mirror will cause a phase shift of pi

the phase is also shifted due to the path difference:

(Δr)(2pi)/λ

so total phase shift is pi + (Δr)(2pi)/λ

3. The attempt at a solution

I can calculate interference at the point on the screen directly in front of the point source:

pi + (Δr)(2pi)/λ = pi + (0.8 mm)(2 pi) / 589 nm

but i'm not sure where to begin finding the fringe spaces on the screen. I can't come up with a function to relate interference on the screen to the path difference caused by the mirror. Any hints would be appreciated!

1. The problem statement, all variables and given/known data

2. Relevant equations

3. The attempt at a solution

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# Homework Help: Interference fringes with reflected light

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