Charging a Conducting Rod: Exploring Charge Behavior and Distribution

In summary: Therefore, the correct answer is that there is positive charge on end A with end B remaining neutral.In summary, the conversation discusses the behavior of charge on conductors, particularly in the context of a long conducting rod suspended by insulating strings. It explores how the charge on the rod is arranged when a charged ball is brought near it and after many contacts with the ball. It also discusses the reaction of end A and end B of the rod when the ball approaches after many previous contacts. The summary concludes that in the conductor, charges distribute evenly and in the given scenario, there is positive charge on end A with end B remaining neutral.
  • #1
grandprix
28
0

Homework Statement



Here is a pretty straight forward question, i just wanted to double check my answers (in bold!)

This problem explores the behavior of charge on conductors. We take as an example a long conducting rod suspended by insulating strings. Assume that the rod is initially electrically neutral. For convenience we will refer to the left end of the rod as end A, and the right end of the rod as end B. In the answer options for this problem, "strongly attracted/repelled" means "attracted/repelled with a force of magnitude similar to that which would exist between two charged balls.

1) A small metal ball is given a negative charge, then brought near (i.e., within about 1/10 the length of the rod) to end A of the rod . What happens to end A of the rod when the ball approaches it closely this first time? It is strongly attracted

It is strongly repelled.
It is strongly attracted.
It is weakly attracted.
It is weakly repelled.
It is neither attracted nor repelled.

2) After a great many contacts with the charged ball, how is the charge on the rod arranged (when the charged ball is far away)? There is positive charge on end A with end B remaining neutral.

There is positive charge on end B and negative charge on end A.
There is negative charge spread evenly on both ends.
There is negative charge on end A with end B remaining neutral.
There is positive charge on end A with end B remaining neutral.

3)How does end A of the rod react when the charged ball approaches it after a great many previous contacts with end A? Assume that the phrase "a great many" means that the total charge on the rod dominates any charge movement induced by the near presence of the charged ball. I am not positive.. are they weakly attracted?

t is strongly repelled.
It is strongly attracted.
It is weakly attracted.
It is weakly repelled.
It is neither attracted nor repelled.

4)How does end B of the rod react when the charged ball approaches it after a great many previous contacts with end A?neither
It is strongly repelled.
It is strongly attracted.
It is weakly attracted.
It is weakly repelled.
It is neither attracted nor repelled.

Homework Equations





The Attempt at a Solution

 
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  • #2
2) In the conducting rod charges distribute through the conductor. In each contact some negative charge is transferred to the rod. So the choice is...

3) Now the rod is negatively charged. Some traces of negative charge may left out in the ball. Then the choice is...
 
  • #3
2) It is weakly repelled (since side B is negative)
3) It is strongly repelled
 
  • #4
grandprix said:
2) It is weakly repelled (since side B is negative)
3) It is strongly repelled
In 2) go through the choices.
In 3) The left out charge in the ball is very small. So the repulsion is..?
 
  • #5
OOPS! I am sorry I read the wrong question..

2) there is negative charge on end A with end B remaining neutral.
3) weak repellsion
 
  • #6
grandprix said:
OOPS! I am sorry I read the wrong question..

2) there is negative charge on end A with end B remaining neutral.
3) weak repellsion
2) is not correct. In the conductor charges cannot remain at one end.
 
  • #7
rl.bhat said:
2) is not correct. In the conductor charges cannot remain at one end.

If they did, the electrons at the charged end would repel each other and distribute themselves evenly in a tiny fraction of a second.
 

What is a conducting rod?

A conducting rod is a solid object made of a material that allows the flow of electric charges, such as metal or graphite. It is often used in electrical circuits to carry and transfer charges.

Why is it necessary to charge a conducting rod?

Charging a conducting rod is necessary because it allows the rod to have a net electric charge, which can then interact with other charged objects or influence the behavior of nearby charges in a circuit.

How is a conducting rod charged?

A conducting rod can be charged by bringing it into contact with a charged object, such as a battery or a Van de Graaff generator. It can also be charged by induction, where a charged object is brought near the rod, causing the charges within the rod to redistribute.

What happens when a conducting rod is charged?

When a conducting rod is charged, the excess charges on the rod will distribute themselves evenly on the surface of the rod. If the rod is connected to a circuit, the charges can flow through the rod and into the circuit, creating an electric current.

Can a conducting rod hold a charge indefinitely?

No, a conducting rod cannot hold a charge indefinitely. As a conductor, it allows charges to flow freely, so any excess charges on the rod will eventually dissipate into the surrounding environment. The rate at which the charge dissipates depends on factors such as the material of the rod and the humidity of the environment.

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