# Charging by Contact

1. Nov 9, 2008

### kiplings01

1. The problem statement, all variables and given/known data
Two uncharged spheres are touching (they are held by insulating stands). A negatively charged rod touches the sphere on the left. After, rod is taken away and the adjacent sphere (the one that the rod did not touch) is separated. What are the net charges on each sphere?

2. Relevant equations

3. The attempt at a solution
After rod is taken away, the 0 charge restores to each spheres touching even before the second sphere is separated from the first that was touched by the rod. OR. the sphere that was touched by the rod is + charged becaused of charging by contact and second sphere that is moved is negatively charged. Which explanation (if any is correct) is right?

2. Nov 9, 2008

### Chi Meson

Sorry, both are wrong.

This was "charge by contact." The negatively charged rod has transferred electrons to the spheres. So what net charge is on the spheres? (the rod is taken away first, so no electrons are jumping back).

3. Nov 9, 2008

### kiplings01

Are they both negatively charged because of the electrons transferred?