1. The problem statement, all variables and given/known data How many rice grains are needed for an electric charge of a certain strength (I dont remember the value now but is it really relevant?) to be equally distributed amongst them? 2. Relevant equations I hope you can answer that :) 3. The attempt at a solution I can only guess. Is there a formula for this? Whats the logic behind this. I was given such a question on a test.