The electrostatic potential V at a point on the circumference of a thin non-conducting disk of radius r and uniform charge density σ is given by equation V = 4 σ r . Which of the following expression

Question

The electrostatic potential V at a point on the circumference of a thin non-conducting disk of radius r and uniform charge density σ is given by equation V = 4 σ r . Which of the following expression correctly represents electrostatic energy stored in the electric field of a similar charged disk of radius R ?

TestHub · Accepted Answer

Charge in layer of width dr dq = 2 π rdr σ Work to bring dq = dU = Vdq dU = 4 σ r ⋅ 2 π rdr σ = 8 π σ 2 r 2 dr U = 8 π σ 2 ∫ 0 R ​ r 2 d r = 3 8 π σ 2 ​ R 3 [0pt]

Physics - Electrostatics Question with Solution | TestHub

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JEE Advanced (2028)