Hello, I've been trying to pin-point the precise definition of charge, but I'm having difficulty. I asked my Professor at college what 'charge' is exactly, and he thought carefully for about a minute, and replied that he really has no idea. The best I can come up with is the following serious of arguments : 1) q= it Charge is current and the time it takes that current to move, which begs the question:what is current? 2) i = V/R Current is the potential drop V across a resistor R. So what is a potential drop ? 3) V= kq/r Potential drop is the the movement of charge q across free space k in a distance r. I think you can begin to see the circuitous reasoning here. This eventually leads to : V=kq/r V=kit/r V=[k(V/R)t]/r V=(krt/R)V ....... just by algebraic reasoning. Help ! What did I do wrong, and can someone seriously answer the question on what a 'charge' really is -- I mean I know a charge has positive and negative, and field lines flow into negative etc, but what is a charge ?