- It can be positive or negative depending on the material.
This is College Physics Answers with Shaun Dychko. This metal sphere is initially neutral before this balloon is brought close to it. After the balloon is nearby but not touching, the charges will re-distribute in the sphere such that the electrons will be attracted to the side closest to the positive balloon. Then the other side of the metal sphere will be positive since the electrons came from there and went over here. But the net charge on this metal sphere is still neutral because it hasn't gained or lost any electrons. The electrons have just moved from one side to the other. So it is now polarized and so this side is positively charged and this side is negatively charged but the net charge is still zero.