What is the electric field of a point charge?

In summary, the conversation discusses the electric field at the origin for a point charge. It is agreed that the field is either zero or undefined at the origin, and it cannot be assigned a value of zero due to issues of size and potential. The concept of Gauss theorem is also mentioned, stating that the field would only be zero if the charge has dimensions.
  • #1
Amin2014
113
3
Assuming the point charge lies at the origin, what is the electric field at the origin? Zero or undefined?
 
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  • #2
undefined
 
  • #3
BvU said:
undefined
I checked some books and you are right. However, I don't understand why we can't we just assign it a value of zero? After all, the charge cannot apply force on itself.
 
  • #4
There is the issue of size. Equal to zero for a point. Zero E would mean constant potential over some region with size. Contradiction !
Amin2014 said:
After all, the charge cannot apply force on itself
No, but it can apply force on a test charge, however close it comes...
No place where that force suddenly drops from near infinity to zero.
 
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Likes Ibix
  • #5
BvU said:
There is the issue of size. Equal to zero for a point. Zero E would mean constant potential over some region with size. Contradiction !

Ok I see. The field is zero at the center of a spherical charge distribution, no matter the size of sphere. So if our charge had dimensions (unlike a point charge), then the field would be zero at the origin.
 
  • #6
Same difference: you refer to Gauss theorem: some charge density times zero volume. Doesn't fly when charge is within zero volume.
 
  • #7
BvU said:
Same difference: you refer to Gauss theorem: some charge density times zero volume. Doesn't fly when charge is within zero volume.
I was validating your answer and completing it. The field would be zero only if the charge has dimensions.
 

1. What is a point charge?

A point charge is a hypothetical charge that has a mass but no physical size. It is often used in physics to simplify calculations and understand the behavior of electric fields.

2. What is an electric field?

An electric field is a region in space where an electrically charged particle experiences a force. It is represented by a vector that describes the direction and strength of the force at any given point.

3. How is the electric field of a point charge calculated?

The electric field of a point charge is calculated using the equation E = kQ/r^2, where E is the electric field, k is the Coulomb's constant, Q is the charge of the point charge, and r is the distance from the point charge.

4. What is the direction of the electric field of a point charge?

The electric field of a point charge always points away from a positive charge and towards a negative charge. This is because like charges repel each other and opposite charges attract each other.

5. How does the electric field of a point charge affect other charged particles?

The electric field of a point charge exerts a force on other charged particles in its vicinity. The magnitude and direction of the force depend on the charge and position of the other particle relative to the point charge. This force can cause the particle to accelerate or change direction.

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