Take the 2-minute tour ×
Physics Stack Exchange is a question and answer site for active researchers, academics and students of physics. It's 100% free, no registration required.

charges are transferred by electrons which we all know but why it cant but it cant be transferred by protons.Well i searched on google where i found similar questions already being asked on many sites.But i ddnt found any answers of them convincing.they were saying that electrons are mobile and similarly protons are busy being nucleons.and similarly someone was saying"By the simple mechanism of separating two things, electrons are pulled out of their Fermi energy levels and into a conduction band to effect charge transference and the creation of a static charge" which i didnt understand at all.

share|improve this question
2  
You can totally transfer charge using protons. Or using Na+ or any kind of charged particle. It happens all the time I think the problem is that electrons are the mobile, charged particles in a solid, so that's what carries the charge in a wire. I bet if you could somehow make a superfluid out of He+ or something you could use that to carry charge like a superconducting wire. –  Paul Apr 12 '13 at 4:59
    
@Paul that could (should) be an answer –  David Z Apr 12 '13 at 5:17
    
@Paul a good example is a chemical battery –  Michael Brown Apr 12 '13 at 5:21
    
simi.arly i couldnt undestand what simple mechanisms were they referring about electrons being pulled out of fermilevels to effect charge transference and the creation of a static charge. –  AaKASH Apr 12 '13 at 5:29
    
@DavidZaslavsky Yeah, I thought I might not have time to come up with some good examples or think it through, so I figured I'd try and put people on what was hopefully the right track. MichaelBrown - Yes. Hard to think of many others, though. I got as far as wet cell battery and ion detectors. –  Paul Apr 12 '13 at 5:29
add comment

4 Answers

up vote 2 down vote accepted

You can totally transfer charge using protons. Or using Na+ or any kind of charged particle. It happens all the time - if you look at how a wet cell battery works, you'll find that while charge across the wire is carried by electrons, current flows along the salt bridge via charged ions (theoretically protons could be among these). I bet if you could somehow make a superfluid out of He+ or something you could use that to carry charge like a superconducting wire.

I think our intuition that electrons are always the charge carriers comes from the fact that:

1.) electrons are very light compared to protons, so if you imagine putting a proton in an electric field and an electron in the same electric field, the electron will be accelerated 1000x more (same charge, 1/1000th the mass). This means that when there is a charge imbalance and either proton or electron flow could alleviate it, the electrons will flow way before the protons are impelled to move.

2.) electrons are the mobile charged particles in a solid - all the protons are bound in nuclei. Since almost all of our intuition about current flow comes from wires or other solid conductors, we're almost exclusively worrying about electron flow.

share|improve this answer
add comment

Protons interact in ways that electrons do not. They get trapped inside nuclei due to the effects of the strong force. Electrons are not affected by the strong force, and so they only get trapped by the electrical attraction to the nucleus which is much weaker in ionized atoms. Therefore it is easier for electrons to move away from one atom to another, transferring charge.

share|improve this answer
add comment

Let me be more pragmatic.

Where do we observe currents? In solids, in liquids and in gases.

What are solids/liquids/atoms made out of? Of electrons bound electromagnetically in shells orbiting tightly bound nuclei which are made out of protons and neutrons. Atoms are neutral

How can me get an atom to be charged?

atom

This helium atom shows how the two electrons surround the nucleus. The reason is the strong electromagnetic field between the two charges of the electrons and the two positive charges of the protons in the nucleus. The protons and neutrons are bound to each other with the strong force. There is a factor of a hundred at least between the force necessary to separate an electron from the electromagnetic field and separating a nucleon from the strong field. In addition the positive bound protons are shielded electromagnetically by the electrons, one has first to remove the electrons to get at a proton.

Thus it is easy to find the Kev energy to remove an electron around the atom than the MeV energy to free a proton. Thus in the huge majority of materials it is the electrons that carry the negative charge, and positive charges one gets from the remaining ions, which are large and therefore smaller mobility ( large crossection for interactions).

The exception is the hydrogen atom, and we get protons to form a strong current in the particle accelerators . Single protons in matter cannot be enough in number to carry the currents a la electrons. They will tie up with an electron and find a pair to make a H2 molecule.

share|improve this answer
add comment

When charges flow through a surface,they can be positive, negative, or both. The direction of conventional current is the direction positive charges flow. In a common conductor such as copper, the current is due to the motion of negatively charged electrons, so the direction of the current is opposite the direction of motion of the electrons. On the other hand, for a beam of positively-charged protons in an accelerator, the current is in the same direction as the motion of the protons. In some cases— gases and electrolytes, for example—the current is the result of the flows of both positive and negative charges. Moving charges, whether positive or negative, are referred to as charge carriers. In a metal, for example, the charge carriers are electrons.

share|improve this answer
add comment

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.