Why Isn't Induced Charge Shown in Electrostatics Problems?

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Homework Help Overview

The discussion revolves around the concept of induced charge in electrostatics, specifically in the context of a thick conducting shell with a charge placed off-center inside it. Participants are examining why induced charges are not explicitly shown in certain electrostatics problems and how this affects the potential and charge distribution.

Discussion Character

  • Conceptual clarification, Assumption checking

Approaches and Questions Raised

  • Participants question the presence of induced charges on the inner and outer surfaces of the shell and their implications for electrical neutrality and potential. There is also inquiry into the symmetry of charge distribution and the validity of certain relationships regarding charge density.

Discussion Status

Some participants have provided insights into the behavior of charges within conductors and the implications for electric fields. There is an ongoing exploration of the assumptions regarding the number of shells and the distribution of induced charges, with no explicit consensus reached.

Contextual Notes

There is a reference to a specific illustration and video that may provide additional context, but the original poster's understanding of the problem setup appears to be a point of confusion. Clarifications about the number of shells and the nature of induced charges are being discussed.

vijayramakrishnan
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Homework Statement


Please see this illustration

http://www.physicsgalaxy.com/lectures/1/57/1006/Solved-Example-1#6 (see question only)

Homework Equations


potential due to a hollow sphere at it's centre = kq/r

The Attempt at a Solution


here won't there be an induced positive charge on the outer surface of inner shell and an induced negative charge on the inner surface of outer shell also to maintain the electrical neutrality of spherical shell?

Why isn't it shown here? And the net potential is also affected by the positive positive charge on the outer surface of inner shell and an induced negative charge on the inner surface of outer shell so won't the answer be different
 
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Hello. Welcome to PF.

I believe there is only one shell, not two.

R1 is the radius of the inner surface of the shell and R2 is the radius of the outer surface of the shell.
 
The question in the link is:
Respected sir, can you explain me why the distribution of positive induced charge is symmetrical at outer surface? I can understand that due to eccentric position of charge distribution of negative induced charge will not be uniform. Is the relation charge density is inversely proportional to the radius of curvature valid for induced charges also? please explain in detail? I will be highly thankful to you.
... there's also a video.
The video problem has a thick conducting shell (inner and outer radii labelled on the diagram) with a small charged placed off-center inside it.

The thing to remember about a conductor is that charges in them can move around. They always move so as to cancel out any electric field that may otherwise have been inside. Thus the solid interior of the conductor must have zero static electric field.

The space between the inner and outer surfaces has no charges - all charges have moved to the surfaces. Negative charges have moved to the inner surface, attracted by the positive charge. The positive charges left behind all repel each other so they go to the outer surface.
 
TSny said:
Hello. Welcome to PF.

I believe there is only one shell, not two.

R1 is the radius of the inner surface of the shell and R2 is the radius of the outer surface of the shell.
iam extremely sorry sir,for not reading the question properly.my sincere apologies.
 
Simon Bridge said:
The question in the link is:
... there's also a video.
The video problem has a thick conducting shell (inner and outer radii labelled on the diagram) with a small charged placed off-center inside it.

The thing to remember about a conductor is that charges in them can move around. They always move so as to cancel out any electric field that may otherwise have been inside. Thus the solid interior of the conductor must have zero static electric field.

The space between the inner and outer surfaces has no charges - all charges have moved to the surfaces. Negative charges have moved to the inner surface, attracted by the positive charge. The positive charges left behind all repel each other so they go to the outer surface.
thank you very much for replying sir.
iam extremely sorry sir,for not reading the question properly.my sincere apologies.
 
vijayramakrishnan said:
iam extremely sorry sir,for not reading the question properly.my sincere apologies.
That's nothing to worry about. We all do that from time to time.
 
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