# Representation Of Diffraction By Vector Summation

1. Dec 26, 2013

### PhysStudentNow

Can someone help me with these parts of this demonstration?

http://demonstrations.wolfram.com/RepresentationOfDiffractionByVectorSummation/

0. Can you define the variables in the model (e.g. s,e, lambda, a, b, z)

1. Where does he get the derivation for phi[i,x] ?

2. Why is delta phi[i,x] needed?

3. I found that zeiger is the "pointer model" in german: http://de.wikipedia.org/wiki/Zeigermodell
but I don't know how it is derived. I don't know how to interpret it...

4. Why is amp[_x] summed over i = 1 to n ? I can see that the diffraction pattern is given by amp[_x] but I don't understand how the length and rotation of the quantum clock is defined by "zeiger".

Here is the source code preview:
http://demonstrations.wolfram.com/s...esentation of Diffraction by Vector Summation

Thank you SO much!
-J