How do we pick where to set electric potential equal to zero?

In summary, the general rule of thumb is to choose a point where the potential is zero when solving problems involving potential. However, for infinitely large charged objects, the potential at infinity may not go to zero, so it is important to consider the behavior of the electric field as well. The choice of the zero point for potential is arbitrary and can be made for convenience in calculations. For practical purposes, there are no truly infinite charged objects, so the potential at infinity is often assumed to be zero.
  • #1
jerro
7
0
Sometimes we set potential to equal zero at infinity, other times at the origin. What's the general rule of thumb here-how do I know which to choose when doing a problem?
 
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  • #2
You generally pick a point where the potential is zero. Infinity usually works, but the potential may not go to zero at infinity if the charged object is infinitely large. Think how the electric field does not diminish as you travel away from an infinite charged plane.
 
  • #3
aftershock said:
You generally pick a point where the potential is zero.
With respect, the only reason for potential being zero at any point is because you've chosen it to be so. Specifically, you choose the arbitrary constant when you integrate the field strength due to the charge configuration in such a way as to make the potential zero at a point of your choice. Choosing that point to be a very way from your charge configuration ('at infinity') makes formulae for potential easier than otherwise.

The example of the infinite plate is interesting. A point 'at infinity' has no meaning in this case. Might as well call the plate's potential zero. But note that there are no infinite plates in practice!
 

Related to How do we pick where to set electric potential equal to zero?

1. How do we determine where to set the electric potential equal to zero?

The electric potential is usually set to zero at a reference point, which is often chosen to be at infinity or at a point where the electric field is known to be zero. This reference point is arbitrary and does not affect the physical behavior of the system.

2. Can we set the electric potential to zero at any point in the system?

No, the electric potential can only be set to zero at a reference point. If the reference point is chosen to be inside the system, the potential at other points in the system will be affected.

3. Why is it important to set the electric potential equal to zero?

Setting the electric potential to zero allows us to measure the potential at different points in the system relative to the reference point. This helps us understand the behavior of the electric field and the flow of electric charge in the system.

4. Can the reference point for the electric potential be changed?

Yes, the reference point can be changed as long as it does not affect the physical behavior of the system. However, it is common practice to choose a reference point that simplifies the mathematical calculations.

5. Is it possible to have a negative electric potential?

Yes, the electric potential can be positive or negative depending on the location and the charge distribution in the system. A negative potential indicates that the electric field is directed towards the reference point, while a positive potential indicates that the electric field is directed away from the reference point.

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