A nonconducting ring of radius R has uniformly distributed positive charge Q. A small part of the ring, of length d, is removed (d << R). The electric field at the centre of the ring will now be
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A nonconducting ring of radius R has uniformly distributed positive charge Q. A small part of the ring, of length d, is removed (d << R). The electric field at the centre of the ring will now be

G1 Physics · Accepted Answer

Step 1: In electrostatic equilibrium, E = 0 inside a conductor and the conductor is an equipotential. Surface charges adjust so the boundary condition field just outside·𝐧 = σ/ε₀ is satisfied. Step 2: For connected conductors set their potentials equal; for sheets use electrostatic pressure p = ε₀E²/2 when appropriate. Step 3: Apply charge conservation and the given geometry. Final: A: directed towards the gap, inversely proportional to R³..