Please wait for the animation to completely load.

The charge on A is 1 nC and the charge on B is -3 nC (position is given in meters and electric field strength is given in newtons/coulomb). Restart.

1. Where does the unknown charge (movable) need to be placed for the electric field at the origin (where the black dot is) to be zero?
2. What is the charge on the unknown charge?

Problem authored by Anne J. Cox.