Uncharged object between two charged plates

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Homework Help Overview

The discussion revolves around the behavior of an uncharged object placed between two charged plates with equal and opposite charges. Participants explore the effects of electric fields generated by these plates on the uncharged object.

Discussion Character

  • Exploratory, Conceptual clarification, Assumption checking

Approaches and Questions Raised

  • Participants discuss the polarization of the uncharged object and the forces acting on its electrons and protons due to the nearby charged plates. Questions arise regarding the implications of the electric field differences between charged spheres and parallel plates, as well as the net effects on the uncharged object.

Discussion Status

The conversation is ongoing, with participants questioning the original poster's assumptions and exploring the interactions between the uncharged object and both charged plates. Some guidance has been offered regarding the nature of electric fields, but no consensus has been reached on the behavior of the uncharged object.

Contextual Notes

Participants are considering the implications of the electric field's homogeneity between the plates and the relative strengths of forces acting on the uncharged object, as well as the assumptions made in the original question.

Biker
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Homework Statement


Imagine if you have two charged plates which have the same magnitude but opposite in charges.
If you place an uncharged object near of the positive plate what will happen?

Homework Equations


I don't think it depends on equations

The Attempt at a Solution


Okay, so If you rub a balloon with your hair, it will gain a negative charge. If you place that balloon really close to really small pieces of paper, It will attract them because the balloon will repel the electrons away from it and the protons don't move so the object will be polarized ( I am pretty sure that I can't say that this effect split the electrons and protons into two different sides equally , can I?)
So the negative charge will attract the protons more than it will attract the electrons because the protons are much closer to it than the electrons. So that will result in a net force to the balloon.

Now back to the question
If I place the uncharged object near the positive plate, the opposite of the above will happen. However, The negative charged plate will attract the protons and the positive plate will repel the protons in the same direction
and the same thing will happen to the electrons but opposite.

The answer in my book was that the uncharged object won't move. But what I think if we assume that it won't move we are just saying that the (distance) between the repelled electrons and attracted protons is just zero which proves that the first idea is wrong.So, What is really happening here?

Thanks in advance.
-Biker
 
Last edited:
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There's a difference between the field from a charged sphere and the field between parallel plates. As you say, the electrons in the object will be attracted towards the positive plate, but what does that mean regarding the interaction with the negative plate?
 
haruspex said:
There's a difference between the field from a charged sphere and the field between parallel plates. As you say, the electrons in the object will be attracted towards the positive plate, but what does that mean regarding the interaction with the negative plate?
Sorry, I didn't get your question. Could you explain what you mean?

The positive plate will attract electrons and the negative plate will repel electrons, But also I have to take into account that the positive plate will repel protons and the negative plate will also attract protons. If that is what you mean

The force of the negative plate will be weaker (because it increases the distance) than the force of the positive plate but they are in the same direction
 
Last edited:
Biker said:
The force of the negative plate will be weaker (because it increases the distance) than the force of the positive plate but they are in the same direction
If the plates are parallel and close to each other, the electric field is homogeneous between them.
 
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