Changes in a Parallel Plate Capacitor – Rankers Physics
Topic: Capacitors
Subtopic: Parallel Plate Capacitor

Changes in a Parallel Plate Capacitor

A parallel plate capacitor is charged and then the battery is removed. If the plates are now moved close to each other then, (A) The charge stored on it, increases. (B) The energy stored in it, decreases. (C) Its capacitance increases. (D) The potential difference between the plates decreases. The correct statement(s) is/are
(B), (C) and (D)
Only (A) and (B)
Only (B) and (C)
(A), (B) and (C)

Solution:

When the battery is disconnected, the charge \(Q\) remains constant. Decreasing the plate separation \(d\) increases capacitance \(C = \frac{\epsilon_0 A}{d}\). This in turn decreases potential difference \(V = \frac{Q}{C}\) and decreases energy stored \(U = \frac{Q^2}{2C}\). Thus, statements B, C, and D are correct.

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