Diffraction equation

  • #1

Homework Statement


I have to find "sinθ" and "d" in the diffraction equation.

Homework Equations


The formula is n(lambda) = d(sinθ)
I have the n, length, width, and hypotenuse.
http://img81.imageshack.us/my.php?image=captureee1.jpg
n=1, L=335 W=42.5 hyp=337.8

The Attempt at a Solution


I forgot how to get the angle for sin. So i'm pretty much stuck.
 

Answers and Replies

  • #2
tiny-tim
Science Advisor
Homework Helper
25,832
251
Welcome to PF!

I have to find "sinθ" and "d" in the diffraction equation.

The formula is n(lambda) = d(sinθ)
I have the n, length, width, and hypotenuse.
http://img81.imageshack.us/my.php?image=captureee1.jpg
n=1, L=335 W=42.5 hyp=337.8

…I forgot how to get the angle for sin. So i'm pretty much stuck.

Hi magma_saber! Welcome to PF! :smile:

Do you mean that if you have, say sinθ = x, you want to get θ as a function of x?

If so, the solution is θ = sin-1x (also written arcsin(x)), which most electronic calculators will do … alternatively, use sine tables "backwards"! :wink:

Or am I misunderstanding the problem? :confused:
 
  • #3
I got sinθ. In my book it says sinθ = opposite over hypotenuse. By doing that i got 42.5/337.8. so sinθ should equal 0.126 right?
Now how do i get "d"? The equation is (n)(lambda)=(d)(sinθ). lambda is 650 btw.
So would this be the equation?
(1)(650)=d(sin0.126)
 
  • #5
tiny-tim
Science Advisor
Homework Helper
25,832
251
I got sinθ. In my book it says sinθ = opposite over hypotenuse. By doing that i got 42.5/337.8. so sinθ should equal 0.126 right?
Now how do i get "d"? The equation is (n)(lambda)=(d)(sinθ). lambda is 650 btw.
So would this be the equation?
(1)(650)=d(sin0.126)

Hi magma_saber! :smile:

I think people have been avoiding answering because you haven't made it clear what W and d are. :confused:

If the correct equation is (n)(lambda)=(d)(sinθ), and if W and hyp are the correct opposite and hypotenuse, then 650 = d times 0.126. :smile:

(not sin(0.126) … 0.126 is the sin :wink:)
 
  • #6
thanks i got it now.
 

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