# Sign of potential difference?

1. Mar 26, 2016

### jtb93

1. The problem statement, all variables and given/known data
A particle begins in a region where positive and negative charges are uniformly distributed and ends up in a region near a negatively charged plate. What is the sign of the potential difference in this case?

2. Relevant equations
N/A

3. The attempt at a solution
I assumed this problem followed "like repels like." I concluded that the potential difference would be negative for a positive particle and positive for a negative particle. The answer in the book says the answer is just negative.

2. Mar 26, 2016

### Staff: Mentor

Hi jtb93,

If the electrode is negatively charged, what does the e-field around the electrode look like? How is potential difference related to the e-field?
Also, you certainly do have equations relevant to this situation. What might they be?

3. Mar 26, 2016

### jtb93

Thanks for the response on my question. I'm honestly lost in physics right now and my professor is of no help. My course is online and the professor has little to no office hours per week.

In the question you responded to, I assume that a negatively charged particle would move towards a positively charged plate, but that does not reflect what is stated in the answer (negative).

4. Mar 26, 2016

### Staff: Mentor

Well, we can always make a few assumptions and see what happens. However, before we do that, can you answer the questions in my previous post?

5. Mar 26, 2016

### jtb93

The electric field would be directed towards electron.
PE=qV?

6. Mar 26, 2016

### Staff: Mentor

Okay. And how is electric potential related to the e-field? What is the electric potential near to this electrode compared to far away?

Well, we don't appear to be working with potential energy in this problem, so do you know another equation? Perhaps one that links electric potential to the e-field or to a charged particle?
Note that you can click the symbol that looks like ∑ in the toolbar above the chat box to bring up a list of symbols. In there you can find Delta (Δ) third in the list.