# Electric Charge and Potential Energy

1. Jul 8, 2007

### BMWPower06

1. The problem statement, all variables and given/known data
A charge is moved from one place to another in an electric field. In which of the following situations will the change in potential energy be NON-ZERO?
True False the charge does not move at all
True False the charge is only moved perpendicular to all electric field lines that it crosses
True False the charge is moved along an equipotential surface
True False the charge is moved to the left by 5 mm and then back to the right by 5 mm
True False the charge is moved along an electric field line, in the same direction as the field

3. The attempt at a solution
My answers are in bold, the computer says im wrong, but it doesnt tell me which answers are wrong, can anyone help me out? I got these answers through reading the chapter in my book.

Thanks

2. Jul 8, 2007

### wildman

The computer is right. You are wrong. Write down why you believe each question is true or false. Include formula if your class includes mathematical formula. Then someone here will help you understand why your thinking is incorrect.

3. Jul 8, 2007

### BMWPower06

I dont think any formula is applicable to this.

According to my book:
1. A charge at rest has potential energy
2. I believe a charge must be moved parallel to the electrical field line
3. Power is equal along the surface so it has potential energy
4. Final position is 0 so potential energy is zero
5. Moving parallel so it has potential energy

any help?

4. Jul 8, 2007

### benzun_1999

"change in potential energy be NON-ZERO" they are not asking you if the charge has potential energy but they are asking abt the change in potential energy.......

5. Jul 8, 2007

### BMWPower06

im still confused as to whether my explainations were correct or not.

6. Jul 9, 2007

### mbrmbrg

Your explanations don't have a whole lot to do with the question. The problem wants to know "in each of these situations, does the potential energy of the particle change?" but your explanations focus on "...does the particle have potential energy?"