Question

A parallel capacitor plate is charged and then isolated. The effect of increasing of plate separation on charge, potential, capacitance respectively are

• A. constant, decreases, decreases
• B. increase, decreases, decreases
• C. constant, decreases, increases
• D. constant, increases, decreases.

Answer 1

The correct option is D constant, increases, decreases.

For parallel plate capacitor $C={\epsilon }_0\frac{A}{d}$ ... 1

For charged capacitor $Q=CV$ .. 2

When a parallel plate capacitor is charged and then isolated the $chargeQ$ on the capacitor remains constant

From 1, Capacitance $C$ is inversely proportional to $d$ (separation between the plates)

Hence on increasing plate separation i.e$d$ the $capacitance$ of the capacitor $decreases$

From 2, $C$ is inversely proportional to $V$ hence potential $V$ $increases$ as $C$ $decreases$

Correct option is $D$