Electric Potential: Solving for Center of Sphere

In summary, The electric potential at the center of a uniformly charged sphere is not zero, as originally believed. It can be calculated by integrating from infinity to the center of the sphere and accounting for the changing electric potential. This is equivalent to calculating the voltage of billions of point charges and summing them together. The electric field within a conducting sphere is zero, so the voltage remains constant throughout the inside of the sphere. This can be explained by the fact that no work is required to move a charge at a constant velocity in a zero electric field. The electric potential at the center of a uniformly charged sphere behaves similarly to that of a point charge up until the surface of the sphere.
  • #1
collegeconfid
9
0

Homework Statement



What is the electric potential at the center of a uniformly charged sphere?

Homework Equations

Ed=-V

The Attempt at a Solution



Integrate from infinity to the center of the sphere and be sure to account for the changing electric potential. I was told that the answer might be zero, but I believe that that is not right. So, am I right?
 
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  • #2
collegeconfid said:

Homework Statement



What is the electric potential at the center of a uniformly charged sphere?

Homework Equations

Ed=-V

The Attempt at a Solution



Integrate from infinity to the center of the sphere and be sure to account for the changing electric potential. I was told that the answer might be zero, but I believe that that is not right. So, am I right?
The answer is not zero, so you're right about that. Think about it this way: what if instead of a sphere of continual charge, you had billions of little, positive point charges in the shape of a sphere. You could calculate the voltage of each one and sum them together to get the total voltage at that point. Well, voltage for a positive charge is always positive and never zero. Therefore, all the point charges would always add and never subtract from the voltage at some point p inside the sphere.

By the way, you know that voltage is the -integral of electric field dx. You also know form Gauss that that sphere of charge up until the surface behaves like a point charge. You also know that the electric field within a conducting sphere is zero. So your voltage calculation is the same as that of a point charge up until r = R (where R is the radius of the sphere) and then the voltage stops becoming bigger - it remains constant throughout the inside of the conductor. This makes sense since the E field is zero in there - it takes no work (no force) to move the charge around at a constant velocity(you needn't push or pull to prevent the electrical force from accelerating it)
 

Related to Electric Potential: Solving for Center of Sphere

1. What is electric potential and why is it important?

Electric potential is a measure of the energy required to move a unit of electric charge from one point to another in an electric field. It is important because it helps us understand and analyze the behavior of electric charges in various systems, such as circuits and particles.

2. How is electric potential different from electric field?

Electric potential is a scalar quantity, meaning it has only magnitude and no direction. On the other hand, electric field is a vector quantity, meaning it has both magnitude and direction. Electric potential is related to electric field by the equation V = -∫E · dl, where V is the electric potential, E is the electric field, and dl is the displacement.

3. How is the electric potential of a sphere calculated?

The electric potential of a sphere can be calculated using the equation V = kQ/r, where k is the Coulomb constant, Q is the charge of the sphere, and r is the distance from the center of the sphere. This equation assumes that the sphere is a point charge and that the distance from the center is much larger than the size of the sphere.

4. How do I solve for the center of a sphere using electric potential?

To solve for the center of a sphere using electric potential, you will need to use the equation V = kQ/r and set it equal to the potential at the center of the sphere, which is V = kQ/R, where R is the radius of the sphere. Then, solve for r to find the distance from the center to the point where the potential is being measured.

5. Can the electric potential of a sphere be negative?

Yes, the electric potential of a sphere can be negative. This can happen if the sphere has a net negative charge, or if the potential is being measured at a point inside the sphere where the electric field is directed towards the center. In this case, the negative sign indicates that work would need to be done to move a positive test charge from infinity to that point.

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