# Electric field and potential of 2 point charges

• soccerscholar
In summary, the problem involves determining at what point the electric field and electric potential are both zero for a -2 μC and 10 μC charge separated by 15.0 cm. The electric field equation is E=(kq1/r1^2)+(kq2/r2^2) and the electric potential equation is V=kq1/r1 + kq2/r2. The key is to determine the direction of the charges and draw a diagram to see where the possible points are. The electric fields from the two charges should point in opposite directions for the net electric field to be zero at that point.
soccerscholar

## Homework Statement

A -2 μC charge and a 10μC charge are separated by 15.0cm. At what point is the electric field zero? At what point is the electric potential zero?

## Homework Equations

E=(kq1/r1^2)+(kq2/r2^2)
V=kq1/r1 + kq2/r2

## The Attempt at a Solution

My main problem is with finding the direction in which the negative and positive charges act on the point where the electric field is 0 and where the electric potential is 0. Can someone explain how to figure out the direction that these charges act? For the electric field, how do you know whether the point is between the two charges, or on either side of one of the charges? I think I can figure out the math from there.

Obviously, The Electric Fields due to the two charges should point in opposite direction for the net E to be zero at that point. You should draw a diagram and see where is/are the possible places.

Okay, makes more sense now. Thanks!

## 1. What is an electric field?

An electric field is a physical quantity that describes the influence that a charged object has on other charged objects in its vicinity. It is represented by arrows that point in the direction of the force that a positive test charge would experience if placed in the field.

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

The electric field of a point charge is calculated using the equation E = kQ/r², where k is the Coulomb's constant, Q is the charge of the point charge, and r is the distance between the point charge and the test charge. This equation is known as Coulomb's law.

## 3. What is the direction of the electric field due to two point charges?

The direction of the electric field due to two point charges depends on the relative positions and charges of the two charges. If the two charges have the same sign (both positive or both negative), the electric field points away from them. If the two charges have different signs, the electric field points towards the positive charge and away from the negative charge.

## 4. How is the electric potential energy of two point charges related to their electric potential?

The electric potential energy of two point charges is directly proportional to their electric potential. The electric potential is the electric potential energy per unit charge, so the higher the potential, the more energy is required to move a charge between the two point charges.

## 5. Can the electric field and potential of two point charges cancel each other out?

Yes, it is possible for the electric field and potential of two point charges to cancel each other out. This occurs when the two charges have equal magnitudes but opposite signs, and are located at the same distance from the test charge. In this case, the electric field and potential would be zero at the location of the test charge.

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