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Easy Java Simulations (2001- ) => Collaborative Community of EJS => Topic started by: lookang on February 08, 2012, 10:23:58 am



Title: Ejs Open Source Long Magnet Falling Through solenoid Model Java Applet
Post by: lookang on February 08, 2012, 10:23:58 am
Ejs Open Source Long Magnet Falling Through solenoid Model Java Applet by lookang, based on a original model by http://www.compadre.org/osp/items/detail.cfm?ID=10327 Magnet Falling Through Ring Model
written by Francisco Esquembre.

[ejsapplet]

adapted to fit the new model of a long magnet made by an array of magnetic dipoles instead of the original model of a single magnet dipole ans also a solenoid made of many coils.

Long Magnet falling through a Solenoid
When a long magnet falls through a Solenoid, current is induced in the Solenoid. This phenomenon is called electromagnetic induction.

According to Faraday’s law, the induced emf is proportional to the negative of the rate of change of magnetic flux Φ. The direction of the induced current is determined by Lenz’s law, the induced current produces magnetic field which tends to oppose the change in magnetic flux that induces such currents.

The voltage induced when a magnet is falling through a Solenoid is simulated in this experiment, where we model the magnet as a vertical set of magnetic 'dipoles'. The current is visualized by very big 'electrons' that move according to the strength of the current.
 
Please, complete this set of Minds-On questions:
Explain the shape (positive and negative peaks) of the recorded signal.
Why the peaks are not symmetric?
At which moment was the magnetic flux changing most quickly?
What was the total change of magnetic flux during the first half of the magnet’s fall - while it was moving in to the coil?
What was the total change of magnetic flux during the second half of the magnet’s fall - while it was moving out of the coil?
How could you change the simulation to increase the magnitude of the sign?
This simulation was created as part of the MOSEM2 project.


Title: Re: Ejs Open Source Long Magnet Falling Through solenoid Model Java Applet
Post by: lookang on February 08, 2012, 10:33:47 am
changes made.

lay the magnet correctly now
changes button to face down as in normal convention of the pole going into solenoid
re arrange layout
add check-box electrons
add slider n input fields to all inquiry variables
figure out a way to draw the electrons but the code is not elegant

thanks to paco for his original code


Title: Re: Ejs Open Source Long Magnet Falling Through solenoid Model Java Applet
Post by: lookang on February 16, 2012, 11:52:04 am
discussion with teacher

I have collated as follows:
1) we need magnet to be of two colors ( red n blue) only. Grey between may give the students the wrong notion that zero emf between the peaks are due to zero magnetic flux.

done!


2) number tagged to every electrons is too near to the rings. Need to space it away from the electrons and ring if possible. So that students can decide the direction of a electron flow and see electron returns when magnet exits.

agree, text = ARIAL BOLD 18
add codes to reposition further