Why Isn't Induced Charge Shown in Electrostatics Problems?

AI Thread Summary
The discussion revolves around the concept of induced charge in electrostatics, particularly in the context of a thick conducting shell with an off-center charge. It clarifies that charges within a conductor can move to cancel any internal electric fields, resulting in zero static electric field inside the conductor. Negative charges accumulate on the inner surface, while positive charges move to the outer surface, maintaining electrical neutrality. The symmetry of the induced charge distribution is emphasized, despite the eccentric position of the internal charge. Overall, the conversation highlights the principles governing charge distribution in conductors and the implications for electric potential.
vijayramakrishnan
Messages
90
Reaction score
0

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
 
Physics news on Phys.org
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.
 
  • Like
Likes Simon Bridge
Thread 'Collision of a bullet on a rod-string system: query'
In this question, I have a question. I am NOT trying to solve it, but it is just a conceptual question. Consider the point on the rod, which connects the string and the rod. My question: just before and after the collision, is ANGULAR momentum CONSERVED about this point? Lets call the point which connects the string and rod as P. Why am I asking this? : it is clear from the scenario that the point of concern, which connects the string and the rod, moves in a circular path due to the string...
Thread 'A cylinder connected to a hanged mass'
Let's declare that for the cylinder, mass = M = 10 kg Radius = R = 4 m For the wall and the floor, Friction coeff = ##\mu## = 0.5 For the hanging mass, mass = m = 11 kg First, we divide the force according to their respective plane (x and y thing, correct me if I'm wrong) and according to which, cylinder or the hanging mass, they're working on. Force on the hanging mass $$mg - T = ma$$ Force(Cylinder) on y $$N_f + f_w - Mg = 0$$ Force(Cylinder) on x $$T + f_f - N_w = Ma$$ There's also...
Back
Top