Two charged conducting spheres X and Y at different potentials are connected by a conducting wire. Which of the following is true?
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → Charge is conserved
Since X and Y are at different potentials, charge flows through the wire when they are joined, until both spheres reach a common potential. During this flow a current passes through the wire.
Option (1) Charge is conserved — Correct. The two spheres and the wire form an isolated system. The charge is only redistributed between X and Y, so the total charge stays the same.
Option (2) Electrostatic energy is conserved — Incorrect. While the charge flows, part of the electrostatic energy is lost in the wire as heat (and electromagnetic radiation). So the final electrostatic energy is less than the initial energy.
Option (3) Both the charge and the electrostatic energy are conserved — Incorrect. Only the charge is conserved. The electrostatic energy decreases because the current in the wire turns part of it into heat.
Option (4) Neither of these is conserved — Incorrect. Charge only moves from one sphere to the other. No charge is created or destroyed, so the total charge does not change.
NCERT (2026-27):
Charge is Conserved – “… Within an isolated system consisting of many charged bodies, due to interactions among the bodies, charges may get redistributed but it is found that the total charge of the isolated system is always conserved.”