# What happens to an electron in the electric field

1. Feb 18, 2012

### hikarigenzo

Hi,im new here. Can you explain to me what happens to the kinetic energy of an electron when it is accelerated in a uniform electric field? My guess is it will go to the positive plate and loses kinetic energy because it isdoing work against the field. Can anyone clarify this?

Thanks

2. Feb 19, 2012

### ZealScience

Firstly, welcome.

Why do you think that it is doing work against the field? Negative charge moving up potential is a decrease in potential energy, i.e. work is done to the electron as it is gaining kinetic energy.

3. Feb 19, 2012

### hikarigenzo

I think maybe my basic is not strong enough. Correct me if im wrong. The electric field direction is from positive to negative right? So the electron need to do work to go to the positive plate. Am i right?

4. Feb 19, 2012

### Drakkith

Staff Emeritus
No, electrons are negatively charged and are attracted to the positive plate. The direction the arrows in the field point in many pictures is meaningless. It could easily be the other way around and it would change nothing. It's simply that like charges repel and opposite charges attract.

5. Feb 19, 2012

### ZealScience

Well, not really. You may work more on the defining formulae. The formulae for field strenth is F=qE. The negativity of q would mean that F would be positive alone the negative direction of E

6. Feb 19, 2012

### hikarigenzo

Thanks for all the replies, so what happens to the kinetic energy and potential energy of it?

7. Feb 19, 2012

### ZealScience

Electrostatic potential decreases of course. Since there is no other force acting on the electron, all these potentials lost to kinetic. Actually, you mentioned accelerated in OP, so what's confusing?

8. Feb 19, 2012

### jim hardy

I have to oversimplify, get a physical picture in myhead and then build up to the mathematical explanation. I think in pictures and envy folks whose mind jumps immediately to the formula.

If i correctly recall a physics class problem from forty++ years ago,
However many volts are across the plates responsible for the field, as it approaches the positive plate the electron's kinetic energy approaches that many electron-volts ..

here's a practical example that even I could follow.

http://wps.aw.com/wps/media/objects/877/898586/topics/topic07.pdf

old jim