# Can u define charge?

1. Jan 13, 2005

### salman_upright

Can u define charge??

We all know that how the bodies acquire charge that is by gaining and losing of negative charges(electrons). How can we define the charge alone?.Further can we say that there are two fundamental properties of matter which are mass and charge? Thanks for kind response.

2. Jan 13, 2005

### Crosson

Charge is a property. It is not a thing. If you try to ask "what is a charge alone?" you encounter the semantic (wording) paradox "a charged what?"

It looks like you want a philosophical answer, but just in case charge is defined in the metric system as:

"one coulomb is the charge that must pass through each of two long wires per second such that the force between the wires is 4 * 10^-7 N when the wires are 1 meter apart."

3. Jan 13, 2005

### dextercioby

In vacuum...

To the OP:mass (rest mass) and ELECTRIC charge are indeed two fundamental properties of nature (particles in the Standard Model of Particles and Interactions).

Daniel.

4. Jan 13, 2005

### pizza1512

I could do with some help here as well...

5. Jan 13, 2005

### rbj

it's $$2 \times 10^{-7}$$ N.

http://physics.nist.gov/cuu/Units/current.html

and a consequence of that definition is that $$\mu_0 = 4 \pi 10^{-7}$$ in metric units. (what is it? Henrys per meter?)

Last edited: Jan 13, 2005
6. Jan 13, 2005

### taeth

A charge is a property of what though? At the Molecular level things are charged based on how many electrons they have or don't have. Mass is a property of matter yet the question of what mass actually is begining to be solved as seen here. http://www.calphysics.org/articles/newscientist.html

7. Jan 13, 2005

### Schneibster

Well, for starters, you ought to read the post I made yesterday on the definition of a force. That will help understand what the effect of charges is, and you'll find out that there is more than just electric charge and mass; there are also particles that have something called weak charge, and other particles that have something called color charge.

Basically, a charge is a property that particles have. The Standard Model of quantum mechanics currently has no definition of what a charge is- just what it does. So the most correct answer is, we don't really know what a charge is. It's just a property that certain kinds of particles have. Forces can act on particles, based on exactly what charge it is, and what value it has. That's about the best you're going to get, unless someone wants to start talking about string theory and how some physicists think there's these extra dimensions that represent degrees of freedom that are the charge, one way and another. But that's a really long conversation; you'd want to go read Brian Greene's The Elegant Universe for all of that stuff.

8. Dec 16, 2010

### yoron

Re: Can u define charge??

So why do we think 'fractional charges' are so strange if it's just a 'property'?
And split it into quasi particles and 'real particles'?

:)

9. Dec 16, 2010

### JDługosz

Re: Can u define charge??

If you were playing cards and got dealt a blue ace, would you think that is strange?

Huh?

10. Dec 16, 2010

### yoron

Re: Can u define charge??

Well from the little I've read about it it's used in condensed matter physics?
And there they name it 'quasiparticles' if I got it right?

As they seem to define those particles somewhat differently.
==

And it's no game of cards as far as I know?
It may be a game though.

But as far as I know we do not know the rules, so, when we learn new ones I wonder why we split it into two instead of trying to incorporate it into one concept?

Last edited: Dec 16, 2010
11. Dec 16, 2010

### JDługosz

Re: Can u define charge??

See here, especially the introduction. What does that have to do with fractional charges being strange?

12. Dec 16, 2010

### yoron

Re: Can u define charge??

That one was what made me wonder in fact :)

13. Dec 16, 2010

### yoron

14. Dec 16, 2010

### yoron

Re: Can u define charge??

Fractional charges are not strange if you consider them a property. 'Properties' are allowed all kind of 'stuff' :) Electrons 'spin' FTL if seen 'classically', photons are mass less and intrinsically time less etc. So what I was wondering was why we considered it necessary to treat it two ways. As quasi particles and as 'real' particles, whatever that last idea then may be?

It's like looking at a car in the darkness and then define the wheels as the 'whole thing' just to find that there are more to it later. and instead of adding to the idea of a 'car' I now start to split it into 'car meeting ground' aka wheels etc. :)

At least from where I stand?
But it might be that there is a perfectly simple explanation that I don't know of?
Does that make my question more understandable?

15. Dec 16, 2010

### JaredJames

Re: Can u define charge??

Yoron, you are aware this post was dead for five years?

16. Dec 16, 2010

### yoron

Re: Can u define charge??

Does that make the subject wrong?
I had a question?

If you feel that way, lock the thread.
I could argue that good threads may well be immortal :)

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