Visual Interpretation of Advanced Electrodynamics

[magiladd]

Hello! I am a junior undergraduate physics major and I am very confused on how to visualize things in my electrodynamics class. Specifically, I am having issues with dielectrics and spheres with constant potentials etc. I usually notice that I am lost in a class when I can no longer draw out a question and what it is asking. Does anyone know of good simulations? I have gone through all the phet ones I can find.

Basically, I want to know what all the charges look like in these situations:
-Concentric spheres with a volume charge density between them where the inner sphere is kept at one potential and the outer sphere is kept at another potential. What does that look like? How does that even happen?
- a dielectric without a conductor has a free charge placed on it. What does the E-field look like? Inside the dielectric and outside of it. I read things like this and can't get past a free charge on a dielectric. How is the charge even placed there? I get too caught up in what is happening that I can't visualize anything.
- Literally, anything that would involve maybe a charge in a conducting sphere vs insulating/ and charges (free) near dielectrics without a capacitor. Really, anything that helped you visualize situations in this class. It is a two-semester class so we haven't gotten to currents or magnetic fields yet, but I think I am pretty good at that cause I can always visualize it.

Thank you I hope this question makes sense!

 

[Vailanor]

One way to visualize these concepts is to use diagrams or sketches. For example, when talking about a dielectric without a conductor, you can draw a diagram showing the electric field lines around the dielectric material and then indicate where the free charge is placed on the dielectric. Similarly, when discussing concentric spheres with a volume charge density between them, you can draw a diagram showing the two spheres and the charge densities in between them. Other than that, there are also some great online simulations and tutorials available to help you visualize these concepts. For example, the Physics Classroom website has an Electromagnetic Induction tutorial which explains how an electric field is created by a dielectric and a free charge, as well as how a capacitor works. Additionally, the PhET Simulations website has several simulations related to electricity and magnetism, including a simulation on Electric Field Hockey which shows how the electric field lines interact with charges. Finally, the Open Source Physics website has a simulation for calculating the electric field of a conducting sphere. I hope this helps!