- #1
solomar
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Homework Statement
Light of wavelength 460nm falls on two slits spaced .3 mm apart. What is the required distance from the slit to a screen if the spacing between the first and second dark fringes is to be 4mm?
Homework Equations
dsin(theta)=(m+1/2)lambda
where d = .3mm
y=4mm
lambda = 460nm
sin(theta)=y/L
The Attempt at a Solution
My problem is I don't understand what to use for m...delta m between the two dark fringes? (3/2-1/2), what am I supposed to use for m?
Using delta m I get:
L=dy/deltam*lambda
L=2.609 meters
Basically all I would really like to know is what in the world do I use for m?
also I am unsure if I am approaching this correctly, do I need to somehow incorporate approximation with small angles? If so, how?