## Wednesday, October 5, 2011

### Ejs Open Source Propagation of Electromagnetic Wave Model Java Applet

Ejs Open Source Propagation of Electromagnetic Wave Model Java Applet
 Ejs Open Source Propagation of Electromagnetic Wave Model Java Applet updated with wavelength showing, different implementation axes possible, side view etc http://weelookang.blogspot.sg/2011/10/ejs-open-source-propagation-of.html https://dl.dropboxusercontent.com/u/44365627/lookangEJSworkspace/export/ejs_users_sgeducation_lookang_emwavewee.jar author: fu-kwun hwang and lookang

 Ejs Open Source Propagation of Electromagnetic Wave Model Java Applet

Ejs Open Source Propagation of Electromagnetic Wave Model Java Applet by Fu-Kwun Hwang remixed by lookang

Full screen applet
Author: Fu-Kwun Hwang and lookang

### Wave model

Electromagnetic radiation is a transverse wave meaning that the oscillations of the waves are perpendicular to the direction of energy transfer and travel. An important aspect of the nature of light is frequency. The frequency of a wave is its rate of oscillation and is measured in hertz, the SI unit of frequency, where one hertz is equal to one oscillation per second. Light usually has a spectrum of frequencies which sum together to form the resultant wave. Different frequencies undergo different angles of refraction.
 Electromagnetic waves can be imagined as a self-propagating transverse oscillating wave of electric and magnetic fields. This 3D diagram shows a plane linearly polarized wave propagating from left to right
A wave consists of successive troughs and crests, and the distance between two adjacent crests or troughs is called the wavelength. Waves of the electromagnetic spectrum vary in size, from very long radio waves the size of buildings to very short gamma rays smaller than atom nuclei. Frequency is inversely proportional to wavelength, according to the equation:
$\displaystyle v=f\lambda$
where v is the speed of the wave (c in a vacuum, or less in other media), f is the frequency and λ is the wavelength. As waves cross boundaries between different media, their speeds change but their frequencies remain constant.
Interference is the superposition of two or more waves resulting in a new wave pattern. If the fields have components in the same direction, they constructively interfere, while opposite directions cause destructive interference.

From http://micro.magnet.fsu.edu/primer/java/polarizedlight/emwave/index.html
 http://micro.magnet.fsu.edu/primer/java/polarizedlight/emwave/index.html

Electromagnetic waves can be generated by a variety of methods, such as a discharging spark or by an oscillating molecular dipole. Visible light is a commonly studied form of electromagnetic radiation, and exhibits oscillating electric and magnetic fields whose amplitudes and directions are represented by vectors that undulate in phase as sinusoidal waves in two mutually perpendicular (orthogonal) planes.

This java applet shows how the electromagnetic wave propagated in the media.
Red segment represent Electric Field
Blue segment represent Magnetic Field
You can modify: T :period of the wave. => wavelength(lamda)=vy*T
Ez: electric field magnitude
vy: wave velocity. =>
Ez/Bx=vy,
where Bx is magnetic field magnitude
Please notice that E/B field are in phase when electromagnetic is travel in vacuum.

other Ejs models
Propagation of Electromagnetic Wave by Fu-Kwun Hwang http://www.phy.ntnu.edu.tw/ntnujava/index.php?topic=35.0
Ejs Electromagnetic Wave Model written by Juan Aguirregabiria edited by Wolfgang Christian http://www.compadre.org/osp/items/detail.cfm?ID=7903

changes
redesign the view made the 3D panel and all drawing in newer Ejs object framework
add vBx = Bx*20 for the scale to be same as in Fu-Kwun version
added boolean to fix un declared error color scheme hints
added for more sense making evol page now in ODE format add "electromagnetic wave direction" and arrow inspired by Juan Aguirregabiria edited by Wolfgang Christian http://www.compadre.org/osp/items/detail.cfm?ID=7903

enjoy!

 The electric field is in a vertical plane and the magnetic field in a horizontal plane

 This 3D diagram shows a plane linearly polarized wave propagating from left to right

Contributions to Wikipedia

Date Name Thumbnail Size User Description
07:01, 5 October 2011Electromagneticsideview.gif (file)190 KBLookang(300*300 for auto animated gif)
06:58, 5 October 2011Electromagneticwave3Dfromside.gif (file)494 KBLookang
06:58, 5 October 2011Electromagneticwave3D.gif (file)544 KBLookang