# Homework Help: Electric potential distance problem?

1. May 19, 2006

### virtuoso_735

Hi everyone I need very badly some help with this problem please:

A force of 0.053 N is required to move a charge of 39 µC a distance of 30 cm in an electric field. What is the size of the electric potential difference between the two points?

Is the electric potential difference the force divided by q (whatever that is) divided by distance? That's what someone told me. I can't find q though. Is that even the right way to to it?

I'm not really sure how to do this at all. I tried to do it for more than an hour yesterday but my teacher is TERRIBLE and I don't get it. The book doesn't really help either. Can someone solve it and guide me through it?

Thanks a whole lot!

2. May 19, 2006

### Curious3141

There are a few relationships involving voltage (or potential difference) V. The one you need here is $$W = QV$$ where V is the potential difference, Q is the charge and W is work done. W is the work required to move a charge Q against a potential difference of V.

Now, use another relationship that you should know between work, force and distance to form an equation and solve for V.

3. May 20, 2006

### xXPhoenixFireXx

You should probably like to know the actual meaning of voltage. I personally like sentences.

Voltage is the potential energy difference, per unit charge.

4. May 20, 2006

### Curious3141

Sorry, sorry, sorry. I misread xXPhoenixFireXx's post. I missed the word "energy" in it, I thought he said "potential difference per unit charge" (which would be wrong). My apologies. I've deleted my post.

Last edited: May 20, 2006
5. May 20, 2006

### big man

haha hate it when that happens. I may as well delete mine as well 'cause I don't want to detract from the the purpose of the thread.

6. May 20, 2006

### virtuoso_735

Okay thanks.

So exactly is q though? I'm confused. Is it 32 in the problem above or do I need to solve for it? If so what equation do I use?

7. May 20, 2006

### big man

The charge Q is the 39 micro Coulombs that was given in the question

8. May 20, 2006

### virtuoso_735

Thanks. Do I need to conver it?

9. May 20, 2006

### Hootenanny

Staff Emeritus
Yes, you should convert it to Coulombs.

~H

Share this great discussion with others via Reddit, Google+, Twitter, or Facebook