# Electric field and potential

• shirel

#### shirel

Hi,

I don't understand why dV/dr=-E

As far as I know:
V=kq/r
E=Kq/(r^2)
so V/r becomes to be E and not -E.

shirel said:
V=kq/r
What's dV/dr for that potential? Compare that to E.

ohh I should derivate the function! thank you :)

## 1. What is an electric field?

An electric field is a region in space where an electrically charged particle experiences a force. It is created by a source charge and is represented by electric field lines that point away from positive charges and towards negative charges.

## 2. How is an electric field calculated?

The strength of an electric field at a point is determined by the magnitude and direction of the source charge and the distance between the source charge and the point. The formula for calculating electric field is E = kQ/r^2, where k is the Coulomb's constant, Q is the source charge, and r is the distance between the source charge and the point.

## 3. What is electric potential?

Electric potential is the amount of work required to move a unit positive charge from infinity to a point in an electric field. It is measured in volts and is a scalar quantity, meaning it has magnitude but no direction.

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

While electric field represents the force experienced by a charged particle, electric potential represents the energy of the charged particle. Electric potential is related to electric field through the equation V = E*d, where V is electric potential, E is electric field, and d is the distance between the point and the source charge.

## 5. What is the relationship between electric field and electric potential?

The relationship between electric field and electric potential is given by the equation E = -dV/dr, where E is electric field, V is electric potential, and r is the distance between the point and the source charge. This equation shows that electric field is the negative gradient of electric potential, meaning that it points in the direction of decreasing potential.