Why do like charges repel each other?

Answer 1

Every system has a tendency to lower it's energy.

For a system of 2 like/unlike charges (q1,q2), the energy of the system is given by the equation
U=k(q1)(q2)/r
where U=potential energy
k=constant for a medium(medium is one in which charges are kept eg air, water etc.)
q1,q2=charges(including their sign, positive or negetive)
r=dist. between charges
For U to be minimum, r should be maximum, everything else kept constant.
therefore, like charges move away to increase r.

Incase of unlike charges one will be negetive and other positive. Let q1 be negetive, so U=k(-q1)(q2)/r
Now, for U to be minimum, r should be minimum so charges attract.
Hence like charges repel and unlike attract.

Answer 2

Unlike Charges Attract

Answer 3

I am not totally sure, but I think that it's a give and take situation where the interaction (being in each other's proximity) forces one pole to 'give up' a number of electrons to get into a state of 'need' and the other takes on that 'excess' and as that interaction takes place, the space in between becomes less until there is nothing to give up or take. Like charges don't have anything they need from the other; what one pole has, the other similar pole has as well. It's all to do with protons and electrons (mostly electrons) and the number of positives and negatives in each pole (matter). In other words, an atom with an equal number of protons and electrons is electrically neutral, since the positive and negative charges balance out. But if there is a difference in the numbers then I guess that's what creates a situation where there is a need and give.

Answer 4

magnetism works only for moving charges and has nothing to do with the asked question. like charges repel each other even if there is no motion. why do they repel each other is not known, they just do.

Answer 5

Electrical Charges
One property of matter is the electric charge. Most sub-atomic particles have either a positive (+) or negative (-) electrical charge. Those that don't are considered neutral. The most common charged particles are the electron and proton. Atoms with an excess of electrons are called negative ions. Those with missing electrons are called positive ions. There is an electrical field that flows between opposite charges, causing an electrical force. This results in an attractive force between the opposite charges and a repelling force between like charges.


Charged particles
An atom is comprised of a nucleus consisting of protons and neutrons and a collection of electrons in orbits or shells around the nucleus. Protons, neutrons and electrons are the most common sub-atomic particles. (See Sub-Atomic Particles for more information.)

Sub-atomic particles have a positive (+) electrical charge, a negative (-) electrical charge, or no electrical charge at all. For example, a proton has a positive electric charge, an electron has a negative electric charge, and a neutron is neutral and has no electrical charge.

Ions
An atom typically has the same number of negative charged electrons as positive charged protons, so its total charge is neutral. But if the atom loses some electrons, it will have more positive charges than negative charges and is called a positive ion. Likewise, if the atom gains an excess of electrons, it is called a negative ion.

Ions are charged particles. They are often involved in static electricity and electrical current on electrolyte solutions such as salt water.

Unipoles
Electrically charged particles are called unipoles, in that they can exist by themselves ("uni" means one). This is different than the case of magnetic poles, where for every N pole, there must be an S pole. Magnets are called dipoles, meaning they must have two poles.

Anti-matter
There is duality in the Universe. That means if there is a left hand, there will be a right hand. That also works with particles.

Since there is a negative charged electron, there is also a version with a positive charge. That anti-electron particle is called the positron. It is the same size and weight as an electron, except it has an opposite charge.

For the positive charged proton, there is the anti-proton that has a negative charge. These oppositely charged particles are called anti-matter.

There is even an anti-neutron. It is still neutral in electrical charge, but it spins in the opposite direction.

Electrical field
An electrical field surrounds every particle that has an electrical charge. By convention, the lines of the electric field are said to radiate from a (+) particle and move towards a (-) particle. It is not certain if there is any direction of radiation, and there is no real good explanation of what the electric field is made of. It's just there.



Electric field lines shown moving from a positive particle

When a positive charged particle (+) like a proton is near a negative charged particle (-) like an electron, the electrical field goes from one to the other.



Electrical field points from (+) to (-)

Forces acting on charged particles
The electrical field acts like a force at a distance and the lines are considered lines of force.

Opposite charges attract
When a positive charged particle is near a negative charged particle, they are attracted to each other by the lines of force.

Static electricity
Static electricity is a good example of opposite charges attracting. If electrons are collected on the surface of one material and positive ions are collected on another surface, the negative and positive charges attract. Either the materials are pulled together or a stream of electrons jumps the gap as a spark.

Note that since protons are in the nucleus, they never collect on a surface in static electricity. Rather, they contribute to the charge of the ions that have lost electrons.

Colliding with anti-matter
If an electron would come near its anti-matter twin, the positron, they would be attracted to each other until they collide. Then they would each be annihilated with a large amount of energy given off in the form of electromagnetic radiation and other smaller sub-atomic particles moving at a high speed. Likewise, if a proton comes into contact with an anti-proton, they will annihilate, giving off a large amount of energy.

Not colliding with other matter
Although they have opposite charges and are attracted to each other, an electron will never combine with a proton. The reason has to do with other forces being involved that keep them apart, as explained in Quantum Theory. This is the same reason that electrons don't go crashing into the positive charged atomic nucleus.

Like charges repel
When particles have the same charge, they repel each other.



Like charges push away from each other

This can be seen in a static electricity experiment. Attach strings to two balloons and rub them both on a wool sweater. Then when you hang the balloons next to each other, you can see the electrical forces push them apart.

In conclusion
An important property of matter is electric charge. Most sub-atomic particles have either a positive (+) or negative (-) electrical charge. Those that don't are considered neutral. Atoms with an excess of electrons or are missing electrons are called ions. There is an electrical field that flows between the positive to negative charges, resulting in an attractive force between the two. Opposite charges attract and like charges repel.

Answer 6

because they have the same charges