Electric energies between 2 pt charges

In summary, when two point charges are separated by a distance r, they will attract each other until there are equal charges of +Q/2 at both points. When one point charge becomes zero in charge, there is a moment of repulsion.
  • #1
kimchi
9
0
+2Q and -Q two pt charges are r apart. AS no external agent exists, they attract to each other and each gains +Q/2 after conduction. Like charges repel. At same distance at r, 2*k(2Q)(-Q)/r = 2*k(Q/2)sq /r + 2 KE...
but what i want to know is that when is the like charges repel...just after a -Q of electrons flow from -Q to 2Q they repel...does conduction happen in a very short time to share equal charge of Q/2 before repulsion?? Or just just after a -Q of electrons flow from -Q to 2Q they repel?
 
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  • #2
That "conduction" is nothing but an electric charge transport process whose main purpose is to equate the electric potential.It happens till the potentials are equal.

Daniel.
 
  • #3
As I understand what you are saying, there are two point charges separated by a distance r. Some mechanism such as a very thin wire provides a path for charge to flow from one point to the second point. The initial charge configuration has -Q at one point and +2Q at the other. A current will flow from one point to the other until there are equal charges of +Q/2 at both points.

As long as one point is positve and the other is negative, there will be attraction. When the charge at the initially negative point is zero, there will be no attraction. As soon as the intially negative point starts accumulating net positive charge there will be repulsion. All of this neglects any charge remaining in the conducting mechanism (wire) that allows the charge to redistribute.

It is of course a hypothetical problem, but it is very important that the charges are point charges. If the charges were distributed on the surface of sphere, for example, When one shere is neutral and the other has charge Q there would be attraction because the charge on the neutral sphere (or on the positive sphere) would not be uniformly distributed. Negative charges would be attracted to and get closer to the positive sphere, resulting in an attraction between the sheres
 
  • #4
No OlderDan. You misunderstood me a bit. My view is that when two point charges separated by a distance r attracts each other spontaneously. When they contact, redistribution of charges begins. Electrons flow from Point charge of -Q to Point charge of +2Q, and when it flows -Q to point charge of +2Q, they become 0 and +Q respectively. At that time, there is no attraction between the 2 new pt charges as they are not of opposite charges. Also as they at point charges of no volume or surface, no induced charges on the neutral one.
Then, how could we said when 2 original pt charges make contact, each on then carry same charges before repulsion?
 
  • #5
just after state of 0 and +Q for the two charges, further flow of charges make them same kind of charge (+charge), repulsion separates them. And no more flow of charge between them happens ><
 

Related to Electric energies between 2 pt charges

1. What is the formula for calculating the electric energy between two point charges?

The formula for calculating the electric energy between two point charges is E = kQq/r, where E is the electric energy in joules, k is the Coulomb's constant (9 x 10^9 Nm^2/C^2), Q and q are the magnitudes of the two point charges in coulombs, and r is the distance between the two charges in meters.

2. How does the distance between two point charges affect the electric energy between them?

The electric energy between two point charges is inversely proportional to the distance between them. This means that as the distance increases, the electric energy decreases. Conversely, as the distance decreases, the electric energy increases.

3. What is the unit of measurement for electric energy?

The unit of measurement for electric energy is joules (J). This is the same unit used to measure other forms of energy, such as mechanical and thermal energy.

4. Can the electric energy between two point charges be negative?

Yes, the electric energy between two point charges can be negative. This occurs when the two charges have opposite signs (one positive and one negative) and the electric energy is considered to be attractive. A positive electric energy indicates a repulsive force between the two charges.

5. How does the magnitude of the point charges affect the electric energy between them?

The magnitude of the point charges directly affects the electric energy between them. As the magnitude of the charges increases, the electric energy also increases. This means that two point charges with larger magnitudes will have a greater electric energy between them compared to two point charges with smaller magnitudes.

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