Help with simulation "Feynman QED" in EJS/board:26-101-

[jirischamberger]

Hallo, i am trying to make the simulation based on the Feynman QED (as you can see on the pictures below) in EJS, but to say the true, i dont even know how to start. My goal is : Two mirrrors, which can be changer (straight and concave), the user will click on any place in the mirrors and in the second window he will see the summation of probability amplitudes. Can anybody help me, please ?

[Fu-Kwun Hwang]

Does the following simulation is what you need?

You can drag S,P to different location.
The red segments show the path which is shertest distance (or smallest time value).

Embed a running copy of this simulation
<applet code='users.ntnu.fkh.feynmanMirror_pkg.feynmanMirrorApplet.class' archive='http://www.phy.ntnu.edu.tw/ntnujava/ejsuser/2/ejs_feynmanMirror.jar' name='feynmanMirror7791' id='feynmanMirror7791' width='534' height='549' mayscript=true><param name='draggable' value='true'></applet>
Embed a running copy link(show simulation in a popuped window)
<a href='http://www.phy.ntnu.edu.tw/ntnujava/msg.php?smfejs=7791' target='smfejs'>Run simulation</a>

Full screen applet or Problem viewing java?Add http://www.phy.ntnu.edu.tw/ to exception site list
Press the Alt key and the left mouse button to drag the applet off the browser and onto the desktop. This work is licensed under a Creative Commons Attribution 2.5 Taiwan License

• Please feel free to post your ideas about how to use the simulation for better teaching and learning.
• Post questions to be asked to help students to think, to explore.
• Upload worksheets as attached files to share with more users.

Let's work together. We can help more users understand physics conceptually and enjoy the fun of learning physics!

[jirischamberger]

Yes, that is exatly what I needed. Thank you very much 

[ahmedelshfie]

In my opinion is excellent applet, thanks prof Hwang for the wonderful work 

[jirischamberger]

I have tried this simulation in a different way : You can drag each point or you can generate (random or Gaussian) the points positions. But I have one problem : Somewhere I do a mistake and I cannot properly display the graphical summation of vectors. Can you help me, please ? Thank you. 

[Fu-Kwun Hwang]

I do not understand what is the problem ?
Could you create snapshot of the image for your simulation (right click mouse and select snapshot) when the problem occurs?
Explain what you want and what you have in the current program.
There is no way to help if I do not understand what is the problem.

[jirischamberger]

Hi, my problem is that i cannot display properly summation of vectors (and resultant vector). It should be looked like Cornu spiral, i think, but I cannot link vectors to each other (vetor A to B, then to C etc. and finally resultant vector), and I cannot find mistake. Thank you.

[Fu-Kwun Hwang]

d1 = Math.sqrt((x1-x2)*(x1-x2)+(y2-y1)*(y2-y1))+ Math.sqrt((x4-x2)*(x4-x2)+(y2-y1)*(y2-y1));
d2 = Math.sqrt((x1-x29)*(x1-x29)+(y2-y1)*(y2-y1))+ Math.sqrt((x4-x29)*(x4-x29)+(y2-y1)*(y2-y1));
d3 = Math.sqrt((x1-x26)*(x1-x26)+(y2-y1)*(y2-y1))+ Math.sqrt((x4-x26)*(x4-x26)+(y2-y1)*(y2-y1));
d4 = Math.sqrt((x1-x24)*(x1-x24)+(y2-y1)*(y2-y1))+ Math.sqrt((x4-x24)*(x4-x24)+(y2-y1)*(y2-y1));
d5 = Math.sqrt((x1-x22)*(x1-x22)+(y2-y1)*(y2-y1))+ Math.sqrt((x4-x22)*(x4-x22)+(y2-y1)*(y2-y1));
d6 = Math.sqrt((x1-x23)*(x1-x23)+(y2-y1)*(y2-y1))+ Math.sqrt((x4-x23)*(x4-x23)+(y2-y1)*(y2-y1));
d7 = Math.sqrt((x1-x25)*(x1-x25)+(y2-y1)*(y2-y1))+ Math.sqrt((x4-x25)*(x4-x25)+(y2-y1)*(y2-y1));
d8 = Math.sqrt((x1-x28)*(x1-x28)+(y2-y1)*(y2-y1))+ Math.sqrt((x4-x28)*(x4-x28)+(y2-y1)*(y2-y1));
d9 = Math.sqrt((x1-x32)*(x1-x32)+(y2-y1)*(y2-y1))+ Math.sqrt((x4-x32)*(x4-x32)+(y2-y1)*(y2-y1));
d10 = Math.sqrt((x1-x27)*(x1-x27)+(y2-y1)*(y2-y1))+ Math.sqrt((x4-x27)*(x4-x27)+(y2-y1)*(y2-y1));
d11 = Math.sqrt((x1-x30)*(x1-x30)+(y2-y1)*(y2-y1))+ Math.sqrt((x4-x30)*(x4-x30)+(y2-y1)*(y2-y1));
d12 = Math.sqrt((x1-x31)*(x1-x31)+(y2-y1)*(y2-y1))+ Math.sqrt((x4-x31)*(x4-x31)+(y2-y1)*(y2-y1));

The above is a copy from part of your code. It is very difficult to read or debug your code.
This is not the way to write a program.
You should have defined an array (e.g. d[12]) and do it with a for loop.
Do the same for x,y,phase, ...

You might want to check out my ejs source from the above example  to find out how to do it with a loop.

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[jirischamberger]

I finally did it. You can change number of path (maximum 100), you can drag Source and Detector, you can drag the points on the mirror. Red ray is the minimum time, green rays are the closest to minimum, you can change lambda. What do you think ?

[jirischamberger]

Sorry, i have a problem with attaching files, trying it again...

[Fu-Kwun Hwang]

You will find Upload new EJS jar file check box at the same line of "Post" button (submit button) when you edit the forum message.

Click that checkbox,  select the jar file before you submit the message.
Then, the EJS simulation in the jar file will appear as applet (part of forum message).
Please try it.

[jirischamberger]

I am trying it...hope it works.

[Fu-Kwun Hwang]

Let me tried it for you!

Embed a running copy of this simulation
<applet code='users.web.Odraz_Jirka_array_pkg.Odraz_Jirka_arrayApplet.class' archive='http://www.phy.ntnu.edu.tw/ntnujava/ejsuser/2/ejs_Odraz_Jirka_array.jar' name='Odraz_Jirka_array8092' id='Odraz_Jirka_array8092' width='361' height='447' mayscript=true><param name='draggable' value='true'></applet>
Embed a running copy link(show simulation in a popuped window)
<a href='http://www.phy.ntnu.edu.tw/ntnujava/msg.php?smfejs=8092' target='smfejs'>Run simulation</a>

Full screen applet or Problem viewing java?Add http://www.phy.ntnu.edu.tw/ to exception site list
Press the Alt key and the left mouse button to drag the applet off the browser and onto the desktop. This work is licensed under a Creative Commons Attribution 2.5 Taiwan License

• Please feel free to post your ideas about how to use the simulation for better teaching and learning.
• Post questions to be asked to help students to think, to explore.
• Upload worksheets as attached files to share with more users.

Let's work together. We can help more users understand physics conceptually and enjoy the fun of learning physics!

[jirischamberger]

Thank you. I forgot one notice - distance is in micrometres. Regards

[transportation]

I have tried this simulation in a different way : You can drag each point or you can generate (random or Gaussian) the points positions.
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