Thin Lens (converging/diverging lens/mirrors)

[Fu-Kwun Hwang]

There are several html files in the ZIP file.
English version is lens_e.html
lens_kr.html is Korean version.
index.html is Chinese version.

[aashoy]

Hey !
I have come to such a virtual laboratory for the first time.It's exciting and stimulating.This's a real resource for teaching image fromation! Thanks a ton for letting it be free.

[gon]

Does offline callback IS possible on windows? I got problem with downloading the source files. Please help me.

[Fu-Kwun Hwang]

Does offline callback IS possible on windows? I got problem with downloading the source files. Please help me.

I just downloaded files without any problem. Please try it again!

[radreamer14]

I really like the programs you've created especialy this one cause you could easily manipulate it and understand the concepts easily.

I just wondering how you did the program. What programs did you use and where could I get one or any similar program that would be somewhat easily to create and manipulate?

Thanks...

[Fu-Kwun Hwang]

This is the first java applet that I have created when I learned java almost 12 years ago (with JDK 1.0.2).

I used a text editor to wrote the code, line by line. Draw arrow, draw line ... etc.
And I have created near 100 java applets by the same way.
But I switch to EJS when listened to the talk by its author (Paco, he and I were invited to give a talk at AAPT meeting at the same session).
Please check the following similar applets which were all created with EJS. (and you can download EJS source and load it inot EJS and watch how I did it. You can modified it to generate new simulation,too.)

1. object in front of concave/convex lens 
2. object in front of concave/convex mirror
3. Lens (thick lens) and Mirror

It is much easier to create new simulation with EJS. This tool focus on the physics instead of java programming.

[radreamer14]

Thank you so much for that.

May we ask permission to use EJS similar to the ray diagrams you've created as a device in an annual science competition in the Philippines if ever we would be able to get to the division, regionals and nationals? Our program is a little different because some lines in our ray diagrams are not shown there and we've also added its functions namely, concave, convex, double concave ad double convex.

Thank you very much!

[Fu-Kwun Hwang]

You are welcomed to use our simulations for educational purpose as long as you list URL to simulation page at this web site when you use it.

[radreamer14]

Does it mean that we may present a similar version of this as our device for a competition(national maybe) as long as we place the URL of the simulation as one of our sources?

Anyway... thank you

[Fu-Kwun Hwang]

Yes, as long as you indicate the original source(URL).  And it will also let the organization aware of the situation.

I did not know what are the rules for the competition. It happened that some one use our simulation in one of the  competition, and they pretend it was done by their team. However, it was found out later when someone in the same competition search the web. So you should let people know what is the work you have really do!  I hope you can win the competition with your own work! 

[radreamer14]

Our program using EJS is used differently that you would not use java codes or the java applet coz we only know HTML and QBASIC. It isn't draggable. In order to operate our program, the user will just use EJS and in the model, he/she may enter different values for the 3 different variables (f for focal length, d for distance of the object from the mirror and h for the height of the object). That is all what we can do.
Anyway.....
We'll do our best to improve our program!
Thanks for everything!

[awzh08@xtreme4.pipex.net]

 

[leeyiren]

Profeesor firstly i downloaded this zipped file, inside dun even have 1 executable jar file. I cannot do anything with it.

secondly, may i know why does the light passing through the optical centre of the lens not get refracted? as in the one passing diagonally. we always draw a straight line. It should have a double refraction or else it is inaccurate for a ray diagram.

[Fu-Kwun Hwang]

There are two different download simulations in this forum:
1. Under JDK1.0.2 simulations (1996-2001): Those simulations are created before 2001. The download ZIP file contain java class file and html files. You need to unzip the file and view the html file (normally, xxx.html where xxx is the same as the downloaded zip file.
2. EJS simulatoions: Those are simulations created with EJS. The download file is a jar file. You can dooble click the jar file to run it. You can open it with EJS when right click the mouse button and select open ejs model option. There are many other options.

The above message are include in the email message you received when you request our server sent you file.

The simulation for this topic is a thin lens. It means that the width of the lens is ignored and approximation has been made. That is why you did not find double refraction for a ray pass through the center. You can find more accurate rar tracing from simulations for thick lens .

[abd]

[i want to save this simulation
how?

[Fu-Kwun Hwang]

Click "get file for offline use" button at the first mesage (where you find the simulation).

[tladewski]

Hi!  Thanks for the great website!

I think I'm not understanding the download procedure for the Thin Lens simulation, because I didn't find a jar file in the download I requested.

The post I read says there are two different downloads, but when I downloaded the files, I only got html files, with some gif, class, and java files.  What should I be doing to get the jar file?

Thanks again for the great work!

[Fu-Kwun Hwang]

There are two different type of downloaded simulations:
1. ZIP file: This is for simulations created before 2001 using JDK1.0.2: You should unzip the file and open index.html with your browser. (There is no jar file, but class files. )
2. JAR file: This is for simulations created after 2001 using EJS.
You can double click jar file to run it locally.

You will get the instruction if you ask our server to send file to your email account (first option).
There is no information if you download it directly (second option).

[Mio-Gonzalez]

[quote:506d759f5b]I see mainly converging lenses collecting rays to one poit (pix A) but do they work another direction? (pix B) any differet solutions/ something usefull to know? I know I could use image conduit but they don't have enought resolution for 2000-3000 pixel CCD-bar/21mm wide...or I'm wrong? In pictures arrow shows direction of ray. [/quote:506d759f5b]
Yes. The path of light ray is reversable. If those parallel light really focus on one single point. You can place a light source at that point can create a parallel light output. Greetings, Max,-*-

Quite interesting question. Does anybody know?

[Mio-Gonzalez]

bikeparts

[quote:506d759f5b]I see mainly converging lenses collecting rays to one poit (pix A) but do they work another direction? (pix B) any differet solutions/ something usefull to know? I know I could use image conduit but they don't have enought resolution for 2000-3000 pixel CCD-bar/21mm wide...or I'm wrong? In pictures arrow shows direction of ray. [/quote:506d759f5b]
Yes. The path of light ray is reversable. If those parallel light really focus on one single point. You can place a light source at that point can create a parallel light output. Greetings, Max,-*-

Quite interesting question. Does anybody know?

hmmmm :-/

[Fu-Kwun Hwang]

My name is Azhar and i am a big fan of your applets and i use it quite a bit in class to teach my classes.

Recently, I was using the thin lens demonstration and i noticed that as i brought the object from distance further away from 1 focal length to exactly to the focal length (object distance = focal length). The light rays go to infinity as expected.

However, as we bring the object from distance less than 1 focal length to exactly one focal length, light rays are shown to come out in the direction of the object, which indicates that there might be a virtual image formed somewhere far  far away.

I genuinely want to know which situation is really true.

This above is an email message I received today.
Light ray goes to infinity when the object is placed at the focus point. i.e. object distance=focus length.
When the object distance is less than focus length(no matter how small the difference might be), it will form virtual image.
When the object distance is more than focus length(no matter how small the difference might be), it will form real image.

From mathematic point of view or with the simulation, we can set object distance=focus length.
However, it is not possible to do so in real life. Because object has finite width and measurement always has finite error.

The simulation was designed so that some student might raise question and think about what really happened.

The purpose of my simulation is not to provide answer to the question student might have, but to provide opportunity for students to think about related physics.

I would suggest you to ask student discuss : is it possible to set object distance = focus length in real life?
Object has finite width. What will be seen when the center of mass of the object is placed at the focus point.
Part of the object distance is less than focus length and part of the object distance is larger than the focus length.

Provide opportunity for student to think is more important than provide answer to the student! :-)

[melnik]

could you please tell me why I am experiencing problems with downloading it now??? Thanks a lot

-*-

[Fu-Kwun Hwang]

I just download it again without any problem. Please try it again or use another browser.

[koclup1580]

thank you so much.