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.