Negative electrostatic potential energy

In summary: D: In summary, the conversation discusses an example of three point charges at the vertices of an equilateral triangle and the calculation of their electrostatic potential energy. The example shows that because the potential energy is negative, the charges would fall together rather than fly apart if released from rest. The concept of negative potential energy is explained as energy being stored in the system and the need to lower it in order to extract the energy.
  • #1
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I have an example in my book showing 3 point charges each at the vertices of an equilateral triangle. q1 = +2 microC, q2 = -2 microC, and q3 = +1 microCoulombs. the distance between each is 0.30m. The example calculates the electrostatic potential energy of the charge configuration, obtaining -0.12 J. The example says that because the electrostatic potential is negative, if the charges were released from rest, they would fall together, not fly apart. "They would fall together, because this would lower their potential energy still further (a larger negative value)." I'm having trouble understanding this principle of negative potential energies. Can someone explain this to me? What does it mean exactly to have negative potential energy? I know there can be a negative change in potential energy, and that is easy to understand using the similar gravitational potential energy. And why must the charges fall together, and why must the potential energy be lowered by having a larger negative value?
 
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  • #2
It might be easier to think of it in terms of the work done in order to bring those charges to the points that they are at from a point of rest. The problem with using gravitational potential as a source of experience is that there is really no terrestrial object that has a negative potential with respect to the earth, i.e. there is no terrestrial massive object that requires positive work to be done to move it from a point infinitely far away to near the earth.
 
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  • #3
Okay, I think I have an understanding about the negative electric potential energy. But why would the charges fall together if they were released from rest?
 
  • #4
Negative potential of any system just signifies that 'energy is stored in the system' , and if we want to extract the energy in this particular system of yours , we need to lower the energy stored in the configuration (by c.o.e) , this is done by making the Potential energy less negative , that is taking the charges as far apart as possible ...

BJ
 

1. What is negative electrostatic potential energy?

Negative electrostatic potential energy is the energy associated with two charged particles in an electric field that are attracted to each other. It is a measure of the potential work that can be done by the electric force as the particles move closer together.

2. How is negative electrostatic potential energy calculated?

Negative electrostatic potential energy is calculated using the formula U = k(q1q2)/r, where k is the Coulomb's constant, q1 and q2 are the charges of the particles, and r is the distance between them.

3. Why is negative electrostatic potential energy important?

Negative electrostatic potential energy is important because it plays a crucial role in understanding and predicting the behavior of charged particles in an electric field. It helps explain phenomena such as attraction and repulsion between particles, and the formation of stable atomic and molecular structures.

4. How does the distance between charged particles affect negative electrostatic potential energy?

The distance between charged particles has a direct impact on the magnitude of negative electrostatic potential energy. As the distance between particles decreases, the potential energy increases, and as the distance increases, the potential energy decreases. This is because the electric force between particles is inversely proportional to the square of the distance.

5. Can negative electrostatic potential energy ever be positive?

While negative electrostatic potential energy is typically associated with attractive forces between charged particles, it is possible for it to be positive. This occurs when the charges of the particles have the same sign, resulting in a repulsive force and a positive potential energy.

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