The behaviour of an uncharged dielectric particle in a capacitor

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SUMMARY

The discussion centers on the behavior of an uncharged dielectric particle, specifically a sphere, placed between parallel plate electrodes in a capacitor. The particle becomes polarized due to the electric field, leading to a non-uniform surface charge distribution. This polarization results in a net force acting on the particle, particularly when it is not centered between the plates. The conversation emphasizes the importance of visualizing electric field lines and charge distributions to understand the particle's movement.

PREREQUISITES
  • Understanding of dielectric materials and their properties
  • Familiarity with electric fields and electrostatics
  • Knowledge of polarization and charge distribution concepts
  • Basic skills in sketching electric field lines and charge distributions
NEXT STEPS
  • Study "Dielectric Sphere in a Uniform Electric Field" for detailed examples
  • Review intermediate E&M textbooks focusing on boundary value problems
  • Learn about the Uniqueness Theorem in electrostatics
  • Explore resources on visualizing electric field lines and charge distributions
USEFUL FOR

Students and educators in physics, particularly those studying electrostatics, as well as anyone interested in the behavior of dielectric materials in electric fields.

kololo
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Homework Statement
What happens to an uncharged particle with a dielectric constant (lower conductivity) when it is placed in a pair of parallel plate electrodes (charged)?
Relevant Equations
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I understand that the particle will be polarised according to its dielectric constant and the electric field across the capacitor.
However, since it is similar to an insulator and electrons do not move in and out of the particle easily, the particle will not be charged.
How then will polarisation cause the particle to move in a pair of parallel plate electrodes? Appreciate it if anyone could guide me/ direct me to any related books/ materials. I am a beginner in this topic, and have been looking through the internet but it's of little avail.
 
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Did you make some sketches of the field and charge distributions?

Let the particle be a sphere of dielectric material. You might start with a sketch where the particle is placed precisely halfway between the charged parallel plates. What does the surface polarization charge distribution look like on the sphere? What does the surface charge distribution look like on each plate? (It won't be uniform.) Roughly, what does the pattern of electric field lines look like? Is there a net force on the particle in this case?

Now suppose the particle is not halfway between the plates. For example, let the particle be placed very close to the positive plate. Sketch the charge distributions and field lines. Can you see that there will now be a net force on the particle? What is the direction of the net force?
 
If you google "Dielectric sphere in a uniform electric field" you will find quite a bit of information including videos. It is a standard problem in electrostatics and is a standard solved example in most intermediate level E&M textbooks as an application of the Uniqueness theorem to boundary value problems.

The question is, what is your level? If you don't quite understand what I'm talking about in the paragraph above, then @TSny's approach is the way to proceed. On the surface of the particle, draw teeny-tiny polarized football-shaped atoms with a ##+## and a ##-## at the two ends, all oriented in the same direction (which direction should this be?), then see what you can say about the net force on the particle.
 
The book claims the answer is that all the magnitudes are the same because "the gravitational force on the penguin is the same". I'm having trouble understanding this. I thought the buoyant force was equal to the weight of the fluid displaced. Weight depends on mass which depends on density. Therefore, due to the differing densities the buoyant force will be different in each case? Is this incorrect?

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