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Enthusiast94
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Homework Statement
A narrow parallel light beam of wavelength 632.8 nm is incident upon a diffraction
ruler (i.e. the light reflects off of the grating rather than passing through it). The
ruler has 600 lines per mm.
Show that the expression for the condition for constructive interference is
m.lambda = d(cos(alpha) - cos(beta))
Homework Equations
m.lambda=d sin(theta)
The Attempt at a Solution
So the right angle triangle has been formed and path difference (green part) = d.cos(alpha). So, how do I get (- d cos (beta)) in my equation. Also, is the path length I shaded correct?
(Diagram attached)