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Single slit diffraction width

  • Thread starter muffintop
  • Start date
  • #1
14
0

Homework Statement


A single slit is illuminated with 630 nm light, and the resulting diffraction pattern is viewed on a screen 2.8 m away.
If the linear distance between the first and second dark fringes of the pattern is 12 cm, what is the width of the slit?


Homework Equations


y=Ltan[tex]\theta[/tex]
W = [tex]\lambda[/tex] m / sin [tex]\theta[/tex]

The Attempt at a Solution


theta = arctan (.12/2.8) = 2.45
W = 630 x 10^-9 x 2 / sin 2.45
 

Answers and Replies

  • #2
Doc Al
Mentor
44,877
1,129
Looks good.
 
  • #3
14
0
I got 29.4 micrometers. It's wrong though.
 
  • #4
Doc Al
Mentor
44,877
1,129
W = 630 x 10^-9 x 2 / sin 2.45
Oops... I missed that factor of 2 before. Why is it there?

Hint: Write expressions for the first dark fringe position and the second dark fringe position, then subtract.
 
  • #5
14
0
I got it thank you so much!
I always get my "m" values wrong.
 

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