Double Slit Interference Question

AI Thread Summary
Light of wavelength 680 nm creates an interference pattern with the fourth-order fringe located 38 mm from the central fringe on a screen 2.0 m away. The equation used to find the slit separation is x = L(λ/d), leading to the calculation of d. The user initially calculated d as 1.4 x 10^-4 m but included a typo in their equation. After clarification, it was confirmed that the approach was correct, with the typo being the only issue. The discussion emphasizes the importance of careful equation setup in solving interference problems.
iurod
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Homework Statement



Light of wavelength 680 nm falls on two slits and produces an interference pattern in which thefourth-order fringe is 38 mm from the central fringe on a screen 2.0 m away. What is the separationof the two slits?

Homework Equations


Sintheta=2m(\lambda2d)

x=L(\lambda/d



The Attempt at a Solution



My givens are:
\lambda= 680nm
L= 2.0m
x438mm

using equation x=L(\lambda/d I got:

0.038 = 2.0m(680 x 10-9(4)/d)
d=2.0m(680 x 10-9(4)/d)/0.038)= 1.4x10-4m

Am I doing this correctly?

Thanks.
 
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iurod said:
I got:

0.038 = 2.0m(680 x 10-9(4)/d)
d=2.0m(680 x 10-9(4)/d)/0.038)= 1.4x10-4m

Am I doing this correctly?
That's how I did it. :approve:
 
iurod said:
I got:

0.038 = 2.0m(680 x 10-9(4)/d)
d=2.0m(680 x 10-9(4)/d)/0.038)= 1.4x10-4m
Oh, except you left the "/d" in there. But I'm guessing that's just a typo. :smile:
 
Last edited:
Thanks! Definitely a typo, sorry about that.
 
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