Physics
Physics
Problem
Two identical, initially neutral metal spheres X and Y are connected by a conducting wire. A negatively charged rod is brought close to sphere X without touching it. While the rod is still near, sphere Y is connected momentarily to ground and then the grounding connection is removed. Finally, the wire between the spheres is disconnected, and the rod is taken away. State whether the final net charge on each sphere is positive, negative, or zero.Intuitive explanation
This problem tests your understanding of electrostatic induction and charge redistribution through grounding. The key insight is that grounding provides a path for charge to flow to/from Earth, which acts as an infinite reservoir at zero potential. Track what happens in each stage: first, the rod induces charge separation in the connected spheres; then grounding sphere Y allows excess charge of one sign to escape; finally, disconnecting traps whatever charge remains on each sphere. Think about which type of charge (positive or negative) would be repelled toward Y and then drained away when it's grounded.
Intuitive explanation
This problem tests your understanding of electrostatic induction and charge redistribution through grounding. The key insight is that grounding provides a path for charge to flow to/from Earth, which acts as an infinite reservoir at zero potential. Track what happens in each stage: first, the rod induces charge separation in the connected spheres; then grounding sphere Y allows excess charge of one sign to escape; finally, disconnecting traps whatever charge remains on each sphere. Think about which type of charge (positive or negative) would be repelled toward Y and then drained away when it's grounded.