⚛️ Physics · Electrostatic Potential and Capacitance · NEET & JEE

Two isolated conducting spheres of radii 2 cm and 4 cm carry equal charges. When they are joined by a thin wire, charge flows from:

Answer: the 2 cm sphere to the 4 cm sphere.

A the 4 cm sphere to the 2 cm sphere
B the 2 cm sphere to the 4 cm sphere
C neither, the potentials are equal
D the wire to both spheres

Correct answer: B. the 2 cm sphere to the 4 cm sphere

Explanation: For equal charge, the smaller sphere has the higher potential (V = kq/r). So charge flows from the 2 cm sphere to the 4 cm sphere until the potentials equalise.

Radial electric field lines and concentric red equipotential lines around a point charge (an electron), with field lines pointing inward

Field lines (radial) and equipotential lines (concentric circles) of a point charge. Equipotential surfaces are always perpendicular to the field lines. Image: Sjlegg, Public Domain, via Wikimedia Commons.

Concept context

Electric potential, equipotential surfaces, potential energy of charge systems, conductors, dielectrics, capacitors, combinations, and energy storage.

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Two isolated conducting spheres of radii 2 cm and 4 cm carry equal charges. When they are joined by a thin wire, charge flows from:

Concept context

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