Java Applet Interactive Tutorials:

Interactive Physics and Math with Java: a set of applet modules created by Sergey Kiselev and Tanya Yanovsky-Kiselev:  The following are particularly relevant or insightful: 

• Single Slit Diffraction
• Interaction of Radiation with an Atom
• The Laser
• Image Formation by a Converging Lens
• Image Formation by a Diverging Lens
• Image Formation by a Diverging Mirror
• Light Dispersion through a Glass Prizm
• Light Dispersion through a Glass Slab
• Total Internal Reflection

• Oscillating 3D Crystal
• Toda Lattice Solitons

• Anharmonic Local Modes

Physics 2000: a set of applet modules created and maintained by the Physics Department of the University of Colorado at Boulder. The following are particularly relevant or insightful:

• Electromagnetic Waves
• Catch the Wave
• Stadium Waves
• Charges and Fields
• The Electric Force
• Electric Force Fields
• Wiggling Charges and Electromagnetic Waves
• Speed of Light

UCD ElectroCard - An Exploratorium for Electromagnetism: another set of applet modules created and maintained by the Physics Department at the University of California at Davis.  The following are particularly relevant or insightful:  

• Radiation - Overview
• Radiation - Oscillating Charge
• Radiation - Retarded Time
• Radiation - Dipole Radiation

Virtual Labs and Simulations: an extensive collection of links to physics applets. 

Physik - Interaktiv I: another extensive collection of links to physics applets. 

NTNU Virtual Physics Laboratory:  Professor Fu-Kwun Hwang of the National Taiwan Normal University has created a wonderful set of applets and two valuable Shockwave optical animations.  The site  NTNU Virtual Physics Laboratory lists a huge number of mirror sites.   We have found the UCLA mirror site to be one of the best maintained.  The following animations are particularly relevant or insightful:

• Under the "Electromagnetic" menu the applet entitled Propagation of Electromagnetic Waves (local copy) is outstanding!!
• Under the "Optics and Light" menu most of the animations are well worth exploring, but the several color shows should not be missed!!

Miscellaneous Simple Calculators:

• Spectrum Tuner Applet: a quickly calculates wavelength, frequency, and energy associated with a given point on a graphical electromagnetic spectrum by Guy McArthur at the University of Arizona.

• In case you even need to use it, here is the Luminance: Unit Conversion

Shockwave Interactive Tutorials: (these all require a Shockwave plug-in)

Visual Quantum Mechanics from the Physics Educational Research Group in the Physics Department of Kansas State University.  The following are particularly relevant or insightful:

 From On-Line Interactive Programs.
 
Spectroscopy Lab Suite
 
• Gas Lamps:
Emission
Absorption
• Solids:
LEDs
Incandescence
• Lasers:
Ruby Laser
Helium Neon Laser
Diode Laser
• Luminsecence:
IR Detector
Fluorescence
Phosphorescence
• Hydrogen Spectroscopy

 
Diffraction Suite
 
• Double Slit Diffraction
• Single Slit Diffraction


Optoelectronic Related

• Energy Band Creator
• Quantum Tunneling
• Color Creator
• Wave Function Sketcher
• Wave Packet Explorer
• Energy Diagram Explorer


The Laser Adventure by Rami Arieli

Roman Pfaff's "first shocked science lab on the www"  at Explore Science - Interactive has some interesting elementary optics and electromagnetism demonstrations. 

The IPPEX Interactive Physics program first developed at the Princeton University Plasma Physics Laboratory has some useful elementary Electricity & Magnetism module.  See, in particular, the following:

• Moving Charge
• Circuits
• Magnetism
• Magnets and Electricity

 

Shockwave demonstrations require installation of the Shockwave plug-in.