Question

Two metal spheres that are initially uncharged are mounted on insulating stands. A negatively charged rubber rod is brought close to, but does not make contact with sphere X. Sphere Y is then brought close to X on the side opposite to the rubber rod. Y is allowed to touch X and then is removed some distance away. The rubber rod is them moved far away from X and Y. What are the final charges on the spheres

Answer 1

Answer:

Sphere X is positively charged while sphere Y is negatively charged

Explanation:

The method described in the given experiment is known as charging by induction. Charging by induction is a method used to charge an object without actually touching the object to any other charged object

When a negatively charged rubber rod is brought near the uncharged sphere X, charges are induced in the metal sphere. Positive charges are attracted to to the rubber rod whereas negative charges are repelled away from the rod. Since the spheres are mounted on insulated stands, the induced charges remain on the sphere. When sphere Y is made to touch sphere X, the negative charges from X flow into Y leaving it with excess negative charges.  When Y is then removed from X, the excess negative charges are then evenly distributed across the surface of Y. Finally, the rubber rod is moved far way from X leaving X with excess positive charges due to the electrons that have flowed from it into Y.