Sphere P has twice the radius of sphere Q

PHYSICS · Single correct · CBSE · Physics · Electrostatic Potential and Capacitance · Electrostatic Potential and Capacitance

Problem

Sphere P has twice the radius of sphere Q. P is initially at +400 V relative to infinity, and Q is at +100 V. The spheres are very far apart and are briefly connected with a thin conducting wire, then separated again. Which statement best describes their potentials after the wire is removed? (a) Both spheres come to a common potential of +300 V+300\,\text{V}, a value between their initial +100 V and +400 V, because the wire forces them to share the same potential. (b) Both spheres remain at +400 V+400\,\text{V} because the sphere that started at the higher potential dominates after contact. (c) Both spheres drop to +100 V+100\,\text{V} since charge flows until the lower-potential sphere is restored to its original value. (d) Both spheres settle at +250 V+250\,\text{V}, the simple average of their initial potentials, because potentials equalize by averaging.

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