A circular parallel-plate capacitor of radius 12 cm is charged by a current of 9 A. Assuming uniform electric field, the displacement current through a concentric circular surface of radius 4 cm between the plates is N ampere. Find N.
Physics · Electromagnetic wave · displacement current and properties of electromagnetic wave
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Question

A circular parallel-plate capacitor of radius 12 cm is charged by a current of 9 A. Assuming uniform electric field, the displacement current through a concentric circular surface of radius 4 cm between the plates is N ampere. Find N.

Physics · Electromagnetic wave · displacement current and properties of electromagnetic wave

G1 Physics · Accepted Answer

For a concentric radius r<R, displacement current through radius r = I(r²/R²). Substitute: I = 9 A, r = 4 cm, R = 12 cm. Therefore, displacement current = 9(4²/12²) = 9(16/144) = 1 A. Hence N = 1.