# Electric Potential of a Circular Rod

• Zythyr
In summary, the conversation discusses the approach to solving a problem involving finding the electric potential due to a continuous charge. The potential is given by dV = (Kdq)/r, but the problem does not specify what dq is. The charge density, which is charge per unit length, is suggested as a possible solution. However, the integral to solve for the potential is not simple and there may be a trick to solve it. The conversation also brings up the concept of surface charge and how it can be used to find the potential. Lastly, there is confusion about the distance of a point on the axis and any point on the ring, as well as whether electric potential is a vector or scalar quantity and how they are added.
Zythyr
http://img136.imageshack.us/img136/7548/44938265by3.jpg

Okay I am not sure how to do this problem without having lambda. I talked to my professor and he said I don't need lambda.

I know that finding the potential due to a continuous charge is

dV = (Kdq)/r

But in this case, I am not sure how to do it. What is dq?

Can someone please explain to me how do I approach doing this problem.

Last edited by a moderator:
Hmm. I haven't figured out how to do the problem with a simple trick, which it sounds like your professor made one in there.

What is the charge density really? Charge per unit length. You can get the charge density and then integrate like normal. Though the integral is not entirely trivial to set up correctly, so there probably is some kind of trick we are missing.

you need the surface charge. You should have something like dV=bda; where b=surface charge of the tube. from there you input it back into to find V=k/r. at least that is how I would approach the problem.

I am confused.

1. What is the distance of the point on the axis and any point on the ring. Is it different for different point?

2. Whether electric potential is a vector quantity or a scalar and how the two type of quantities are added?

## 1. What is electric potential?

Electric potential is a measure of the potential energy per unit charge at a specific point in an electric field. It is often described as the amount of work needed to move a unit charge from a reference point to the specific point in the electric field.

## 2. How is electric potential different from electric field?

Electric field is a vector quantity that describes the strength and direction of the electric force on a charged particle. Electric potential, on the other hand, is a scalar quantity that describes the energy of a charged particle at a specific point in the electric field.

## 3. What is the equation for electric potential?

The equation for electric potential is V = kQ/r, where V is electric potential, k is a constant, Q is the charge of the particle, and r is the distance between the particle and the source of the electric field. For a circular rod, the equation would be V = kQ/r, where Q is the total charge of the rod and r is the distance from the center of the rod.

## 4. How does the electric potential of a circular rod vary with distance?

The electric potential of a circular rod varies inversely with distance. This means that as the distance from the center of the rod increases, the electric potential decreases. This relationship is described by the equation V = kQ/r, where V is electric potential, k is a constant, Q is the total charge of the rod, and r is the distance from the center of the rod.

## 5. How is the electric potential of a circular rod affected by its charge?

The electric potential of a circular rod is directly proportional to its charge. This means that as the charge of the rod increases, the electric potential also increases. This relationship is described by the equation V = kQ/r, where V is electric potential, k is a constant, Q is the total charge of the rod, and r is the distance from the center of the rod.

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