Final answer:
Touching a positively charged metal plate to a neutral metal sphere results in the sphere gaining a positive charge due to the transfer of electrons from the sphere to the plate.
Step-by-step explanation:
When Oriana touches a positively charged metal plate to a neutral metal sphere, the charge of the metal sphere changes such that it has an excess of positive charge. This is because when a charged conductor comes into contact with another conductor, charges can move between them. In this case, some of the positive charge from the metal plate will transfer to the neutral sphere, thus giving the sphere a positive charge. Once the metal plate is removed, the sphere retains this positive charge. It's important to note that in a solid conductor such as a metal sphere, what is actually moving are the electrons. A positive charge is transferred by electrons moving in the opposite direction. When a sphere becomes positively charged, it means that it has lost electrons, leaving it with more protons than electrons, and hence a net positive charge.