In a charged capacitor connected to a battery, then disconnected, which statement is true?

In a charged capacitor connected to a battery, then disconnected, which statement is true?

• A. The voltage remains equal to battery and current continues to flow
• B. The capacitor discharges instantly
• C. The capacitor stores charge with potential difference equal to battery; circuit current stops
• D. The dielectric breaks down

Answer: (C)

A capacitor holds charge by building up equal and opposite charges on its plates, creating a voltage across it. When it is connected to a battery, charge flows until the plate voltage matches the battery voltage. If you then disconnect the capacitor, there is no closed path for current to flow, so the charges can’t move and the current stops. In the ideal case with no leakage, the charge remains on the plates, so the voltage across the capacitor stays equal to the battery voltage. The result is that the capacitor stores charge with a potential difference equal to the battery, and the circuit current stops. The other statements would require a path for discharge, ongoing current, or a breakdown of the dielectric, none of which is implied in the ideal, open-circuit after disconnection.

A capacitor holds charge by building up equal and opposite charges on its plates, creating a voltage across it. When it is connected to a battery, charge flows until the plate voltage matches the battery voltage. If you then disconnect the capacitor, there is no closed path for current to flow, so the charges can’t move and the current stops. In the ideal case with no leakage, the charge remains on the plates, so the voltage across the capacitor stays equal to the battery voltage. The result is that the capacitor stores charge with a potential difference equal to the battery, and the circuit current stops. The other statements would require a path for discharge, ongoing current, or a breakdown of the dielectric, none of which is implied in the ideal, open-circuit after disconnection.