Diffraction: how to know the amount of slits from a diffraction pattern?by Paavo T Tags: diffraction, fraunhofer, slits 

#1
May1210, 02:43 AM

P: 1

1. The problem statement, all variables and given/known data
There are at least two different situations. If you have N2 middle minimums, the amount of slits is N. Please, see the bottom left picture. The case with no such thing is the question about. How can I determine the amount of slits with the other cases? Please, see the other pictures in the link. 2. Relevant equations [tex]a sin(\theta) = n \lambda[/tex] where a is the width of the separtion of two sidebyside slits. Intensity formula with angle: [tex]I = I_{0} \left[ \frac{sin \left( \pi b sin \left( \frac{\theta}{\lambda} \right) \right) }{\pi b sin \left( \frac{\theta}{\lambda}} \right) \right]^{2} \left[\frac{sin\left(N \pi a sin\left(\frac{\theta}{\lambda}\right)\right)}{sin \left( \pi a sin\left( \frac{\theta}{\lambda}}\right) \right) \right]^{2}[/tex] 3. The attempt at a solution If you have 2 slits, then you have 5 main maximums. My proposal that the amount of maximums is 2N+1, where N is the amount of slits was rejected, by my teacher. You can see that it is not the case from the Wolfram link above. Then I tried to delve into the wave function but I am really lost with it. Cannot see how it helps in finding the the number of slits. 


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