Electrostatics problem

1. Aug 15, 2009

logearav

1. The problem statement, all variables and given/known data

three small identical balls have charges -3C,8C and 4C respectively. they are brought in contact and separated. calculate charge on each ball?

2. Relevant equations

q=(q1+q2+q3)/3

3. The attempt at a solution
what is the need for dividing by 3. why not simply add the charges q1+q2+q3

Last edited: Aug 16, 2009
2. Aug 15, 2009

Staff: Mentor

That would give you the total charge, not the charge per ball.

3. Aug 16, 2009

logearav

sir, it has already been mentioned about the charge possessed by each individual ball. When they come in contact some redistribution of charge occurs. if they are separated wont they get their initial charges?

4. Aug 16, 2009

Staff: Mentor

No, why would they? They retain no "memory" of their initial charges.

Here's an example that might make it clear. Imagine two identical balls, with charges of +5 and -5 units. When brought together the charge redistributes, adding to zero. There's no longer a charge on the balls, they are neutral. If you had two uncharged balls together, would you expect them to gain a charge as they are separated?

5. Aug 18, 2009

logearav

Thanks sir. i understood now