### Author Topic: Atomic Spectra of Hydrogen and red shift  (Read 50346 times)

#### Fu-Kwun Hwang

• Hero Member
• Posts: 3062
##### Atomic Spectra of Hydrogen and red shift
« on: August 05, 2007, 12:07:40 pm »
This applet let you play with atomic spectra of hydrogen.

The wavelengths of hydrogen spectra lines can be described by the following equation:

1/?=RH*(1/n12-1/n22)
where RH=1.0973732*107 m-1

You can change n1 with the slider bar. The program will plot a series of spectrum lines.
You might want to change the xmax(at the right) to see the full range of the spectra.
One of the line is thicker and with an arrow is the one with n2 equal to slider bar value.

Click within simulation region will toggle "visible spectra range".

You can also find out how the red shift of the spectra calculated from Hubble's law.
v=H0 D where the recessional velocity is proportional to the distance of the star to the earth (D). You can adjust the distance of the star.
And see the red shift of the hydrogen spectra from that star due to the expansion of the universe.
-*-
n1=1 : Lyman series (Ultraviolet)
n1=2 : Balmer series (Near Ultraviolet and Visible)
n1=3 : Paschen series (Infrared)
n1=4 : Brackett series (Infrared)
n1=5 : Pund series (Infrared)

Full screen applet or Problem viewing java?Add http://www.phy.ntnu.edu.tw/ to exception site list
• 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!

#### NagySandorIstvan

• Newbie
• Posts: 19
##### Re: Atomic Spectra of Hydrogen and red shift
« Reply #1 on: August 26, 2009, 03:32:04 pm »
Dear Prof. Hwang,
The redshift applet is a very good idea, because it shows that the individual spectrum lines are not equally shifted, but the shift depends on the wavelength (or the frequency).
I have a comment though:
If c is the speed of light, then the distance unit should be millions of light years. Then the numerical value 3.3 indicated for the distance on the starting screen (which probably comes from 1 Mpc = 3.26 million light years) gives then approximately the correct value for the Hubble speed in units of c. (If calculated with H0 = 74 (km/s)/Mpc.)
Is it possible to translate the applet to Hungarian?
Best regards,
Sandor Nagy

#### Fu-Kwun Hwang

• Hero Member
• Posts: 3062
##### Re: Atomic Spectra of Hydrogen and red shift
« Reply #2 on: August 26, 2009, 05:46:49 pm »
It is easy to translate string in EJS into different language format:
3. RIght Click in the simulation window: select translation from GUI options
A window will popup with all the strings. Type in your translation into second column (modify original values) and save it when you are done.
4. It should be loaded automatically when you run it next time.

#### NagySandorIstvan

• Newbie
• Posts: 19
##### Re: Atomic Spectra of Hydrogen and red shift
« Reply #3 on: August 26, 2009, 08:37:40 pm »
Thank you Prof. Hwang,
The translation worked fine, except that the information window that pops up with the simulation is empty, although I translated that too before I loaded down the program. Is there a way to block the empty window?
I will write the help in html.
Best,
Sandor

#### Fu-Kwun Hwang

• Hero Member
• Posts: 3062
##### Re: Atomic Spectra of Hydrogen and red shift
« Reply #4 on: August 27, 2009, 01:14:13 am »

If you have installed EJS in your computer:
You can Right click open EJS model , and the source code will be open in EJS environment.
You can change those label in EJS and recompile it again (Click green trigangle button).

#### NagySandorIstvan

• Newbie
• Posts: 19
##### Re: Atomic Spectra of Hydrogen and red shift
« Reply #5 on: August 29, 2009, 12:36:19 am »
I will do that. However I have another problem. I have just uploaded the Hungarian version on the server for the students, but if you open the page
http://www.chem.elte.hu/Sandor.Nagy/NewClearGlossy/Java/Hubble_Hwang/index.html
the applet will probably not run. The same package runs nice on my computer both at home and at my office at university. I don't know what the problem can be.
I also show you the screen as it is supposed to look like. (See the attachment.) The reason I am showing is that it contains a formula in English which is a picture not a string. I think, it would be better if instead of the word "Wavelength" there would be a Greek letter "lambda".
What do you think?
Best,
Sandor

#### Fu-Kwun Hwang

• Hero Member
• Posts: 3062
##### Re: Atomic Spectra of Hydrogen and red shift
« Reply #6 on: August 29, 2009, 09:50:54 am »
If you open the source in EJS, you will find there is a veriable named:eqn withvalue "wavelength \lambda=R_H(\frac{1}{n_1^2}-\frac{1}{n_2^2})";

You can add TeX mathematics formula syntax and it will display it. However has to be written as \
in order for java to process it as .

The problem seems due to incompatiable type of java. I just re-compiled it again, please try to download it again.

#### NagySandorIstvan

• Newbie
• Posts: 19
##### Re: Atomic Spectra of Hydrogen and red shift
« Reply #7 on: August 29, 2009, 09:04:35 pm »
Please check the applet on your page. It shows error on my computer after a long time of waiting. The rest of the applets are OK.
Sandor

#### lookang

• Hero Member
• Posts: 1774
• http://weelookang.blogspot.com
##### Re: Atomic Spectra of Hydrogen and red shift
« Reply #8 on: August 29, 2009, 11:53:59 pm »
the error message is

cHotEqn V 4.02 cHotEqn
at java.security.AccessControlContext.checkPermission(Unknown Source)
at java.security.AccessController.checkPermission(Unknown Source)
at java.lang.SecurityManager.checkPermission(Unknown Source)
at sun.awt.SunToolkit.getImageFromHash(Unknown Source)
at sun.awt.SunToolkit.getImage(Unknown Source)
at atp.d.a(Unknown Source)
at atp.d.a(Unknown Source)
at atp.cHotEqn.if(Unknown Source)
at atp.cHotEqn.if(Unknown Source)
at atp.cHotEqn.try(Unknown Source)
at atp.cHotEqn.new(Unknown Source)
at atp.cHotEqn.getPreferredSize(Unknown Source)
at java.awt.GridLayout.preferredLayoutSize(Unknown Source)
at java.awt.Container.preferredSize(Unknown Source)
at java.awt.Container.getPreferredSize(Unknown Source)
at javax.swing.JComponent.getPreferredSize(Unknown Source)
at java.awt.BorderLayout.layoutContainer(Unknown Source)
at java.awt.Container.layout(Unknown Source)
at java.awt.Container.doLayout(Unknown Source)
at java.awt.Container.validateTree(Unknown Source)
at java.awt.Container.validateTree(Unknown Source)
at java.awt.Container.validateTree(Unknown Source)
at java.awt.Container.validateTree(Unknown Source)
at java.awt.Container.validateTree(Unknown Source)
at java.awt.Container.validateTree(Unknown Source)
at java.awt.Container.validateTree(Unknown Source)
at java.awt.Container.validateTree(Unknown Source)
at java.awt.Container.validateTree(Unknown Source)
at java.awt.Container.validateTree(Unknown Source)
at java.awt.Container.validate(Unknown Source)
at sun.plugin.util.GrayBoxPainter$2.run(Unknown Source) at java.awt.event.InvocationEvent.dispatch(Unknown Source) at java.awt.EventQueue.dispatchEvent(Unknown Source) at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source) at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source) at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source) at java.awt.EventDispatchThread.pumpEvents(Unknown Source) at java.awt.EventDispatchThread.pumpEvents(Unknown Source) at java.awt.EventDispatchThread.run(Unknown Source) java.security.AccessControlException: access denied (java.io.FilePermission Fonts14.gif read) at java.security.AccessControlContext.checkPermission(Unknown Source) at java.security.AccessController.checkPermission(Unknown Source) at java.lang.SecurityManager.checkPermission(Unknown Source) at java.lang.SecurityManager.checkRead(Unknown Source) at sun.awt.SunToolkit.getImageFromHash(Unknown Source) at sun.awt.SunToolkit.getImage(Unknown Source) at atp.d.a(Unknown Source) at atp.d.a(Unknown Source) at atp.cHotEqn.if(Unknown Source) at atp.cHotEqn.if(Unknown Source) at atp.cHotEqn.try(Unknown Source) at atp.cHotEqn.new(Unknown Source) at atp.cHotEqn.getPreferredSize(Unknown Source) at java.awt.GridLayout.preferredLayoutSize(Unknown Source) at java.awt.Container.preferredSize(Unknown Source) at java.awt.Container.getPreferredSize(Unknown Source) at javax.swing.JComponent.getPreferredSize(Unknown Source) at java.awt.BorderLayout.layoutContainer(Unknown Source) at java.awt.Container.layout(Unknown Source) at java.awt.Container.doLayout(Unknown Source) at java.awt.Container.validateTree(Unknown Source) at java.awt.Container.validateTree(Unknown Source) at java.awt.Container.validateTree(Unknown Source) at java.awt.Container.validateTree(Unknown Source) at java.awt.Container.validateTree(Unknown Source) at java.awt.Container.validateTree(Unknown Source) at java.awt.Container.validate(Unknown Source) at org.colos.ejs.library.LauncherApplet.captureWindow(Unknown Source) at users.ntnu.fkh.hydrogen_pkg.hydrogenSimulation.(hydrogenSimulation.java:21) at users.ntnu.fkh.hydrogen_pkg.hydrogen.(hydrogen.java:77) at users.ntnu.fkh.hydrogen_pkg.hydrogenApplet.init(hydrogenApplet.java:22) at sun.plugin2.applet.Plugin2Manager$AppletExecutionRunnable.run(Unknown Source)

#### NagySandorIstvan

• Newbie
• Posts: 19
##### Re: Atomic Spectra of Hydrogen and red shift
« Reply #9 on: August 30, 2009, 01:03:55 am »
Yes, something like that,
Sandor

#### Fu-Kwun Hwang

• Hero Member
• Posts: 3062
##### Re: Atomic Spectra of Hydrogen and red shift
« Reply #10 on: August 30, 2009, 06:13:07 pm »
I remove \lambda command inside TeX string and it is working fine now.

However, it was not able to read some font due to security reason when running as applet.

#### NagySandorIstvan

• Newbie
• Posts: 19
##### Re: Atomic Spectra of Hydrogen and red shift
« Reply #11 on: September 01, 2009, 12:38:54 am »
Thanks, I have uploaded the new version and it works fine.
You can check it on my page at
http://www.chem.elte.hu/Sandor.Nagy/NewClearGlossy/Java/Hubble_Hwang/index.html
However, I have a suggestion (maybe two):
I think, the "wavelength" formula (and Rydberg's constant) should be removed from the applet area. One reason is the problem with translation. The second is: it should be the reciprocal of the wavelength. The third is: you explain it correctly anyway. The fourth is: the applet would look better.
Best,
Sandor

#### Fu-Kwun Hwang

• Hero Member
• Posts: 3062
##### Re: Atomic Spectra of Hydrogen and red shift
« Reply #12 on: September 01, 2009, 12:12:56 pm »

Yes, there is a mistake for the forum in the applet. It has been modified according to your suggestion.

#### NagySandorIstvan

• Newbie
• Posts: 19
##### Re: Atomic Spectra of Hydrogen and red shift
« Reply #13 on: September 01, 2009, 09:04:36 pm »
I have uploaded the new version.
It works fine and it looks great.