Question

The net charge on a charged capacitor is

• A. zero
• B. 1 \(\mu\) C
• C. 1 C
• D. infinite

Hint:

Be careful with the wording. "Charge on a capacitor" usually means the magnitude of charge on the positive plate (\(Q\)). "Net charge on a capacitor" or "total charge of the capacitor" means the sum of charges on both plates, which is always zero for an isolated, charged capacitor.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
A capacitor is a device that stores electrical energy in an electric field. It typically consists of two conductive plates separated by an insulator (dielectric). The question asks for the net or total charge on the capacitor as a whole when it is charged.
Step 2: Detailed Explanation:
When a capacitor is connected to a voltage source (like a battery), the source moves electrons from one plate to the other.
- The plate that loses electrons becomes positively charged. Let's say it acquires a charge of \(+Q\).
- The plate that gains an equal number of electrons becomes negatively charged. It acquires a charge of \(-Q\).
The term "charge on a capacitor" conventionally refers to the magnitude of the charge on one of the plates (i.e., \(Q\)).
However, the *net charge* of the capacitor as a complete, isolated device is the algebraic sum of the charges on both plates.
\[ Q_{net} = (+Q) + (-Q) = 0 \] Step 3: Final Answer:
Since one plate has a charge of \(+Q\) and the other has a charge of \(-Q\), the total net charge on the charged capacitor is zero. Therefore, option (A) is correct.