Conducting Rod in Electric Field

In summary, the conversation discusses the potential difference that may be developed in an uncharged conductor placed in a uniform electric field, and how it is related to the field. It is determined that a potential difference may develop, but it will be short lived as the charge inside the conductor will rearrange itself to eliminate the potential drop. There is also a discussion about the concept of bound and free charges in relation to this scenario. However, the validity of the statement that there will be no potential drop across the conductor is questioned, and it is suggested that there will actually be a potential difference maintained within the conductor due to the superposition of the imposed and internal electric fields.
  • #1
Apteronotus
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0
If an uncharged conductor, a metal rod say, is placed in a uniform electric field E, parallel to the field (see figure), does it develop a potential difference between its two ends?

If so, how is the potential difference related to the field E?
 

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  • #2
Apteronotus said:
If so, how is the potential difference related to the field E?

By the definition, the electric potential, as the energy required to bring a point charge from point B to point A, is given by the negative integral of E over the distance dr from B to A. That is,
[tex]\int^{B}_{A}Edr[/tex]
Just try to apply this on your case where A and B are different positions of the ends.
 
  • #3
Well, if there is a potential difference, it will be very short lived. Since this is a conductor, the charge inside the conductor will re-arrange itself so that there is no potential drop across the conductor.
 
  • #4
kcdodd said:
Well, if there is a potential difference, it will be very short lived. Since this is a conductor, the charge inside the conductor will re-arrange itself so that there is no potential drop across the conductor.

Yes I think you're right! And remember the concept of bound and free charges.
 
  • #5
kcdodd said:
Well, if there is a potential difference, it will be very short lived. Since this is a conductor, the charge inside the conductor will re-arrange itself so that there is no potential drop across the conductor.

Actually, I'm not sure this is true. I've given the problem some thought since my original posting. I think a potential difference will in fact develop (and maintain) within the conductor. It's effect will be an electric field within such that the magnitude of the field will be equal to that of the imposed electric field (outside field) and will point in the opposite direction.

So the superposition of the two fields will be zero within the conductor.
 
  • #6
Yes, the field will be zero within the conductor. So, if you do a line integral from one end to the other you will get zero for the potential difference.
 

1. What is a conducting rod?

A conducting rod is a cylindrical object made of a material that allows electricity to flow through it. It is used as a component in electrical circuits to carry current from one point to another.

2. How does a conducting rod behave in an electric field?

A conducting rod placed in an electric field will experience a force due to the presence of charged particles in the field. This force will cause the rod to move in the direction of the field lines.

3. What factors affect the behavior of a conducting rod in an electric field?

The behavior of a conducting rod in an electric field is affected by the strength of the electric field, the length and thickness of the rod, and the material it is made of. The charge on the rod also plays a role in its behavior.

4. How can a conducting rod be used to measure the strength of an electric field?

A conducting rod can be used as a simple tool to measure the strength of an electric field. By placing the rod in the field and measuring the force acting on it, the strength of the electric field can be calculated using the formula F = qE, where F is the force, q is the charge on the rod, and E is the strength of the electric field.

5. Can a conducting rod be used to shield against an electric field?

Yes, a conducting rod can act as a shield against an electric field. When placed in an electric field, the rod will experience a force that will cause it to align itself in a way that cancels out the electric field inside the rod. This is known as the Faraday cage effect and is used in many applications to protect sensitive equipment from external electric fields.

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