Which component stores energy in an electric field, not primarily through chemical storage?

Which component stores energy in an electric field, not primarily through chemical storage?

• A. Carbon pile
• B. Battery
• C. Capacitor
• D. Ammeter

Answer: (C)

The key idea is how energy is stored. A capacitor stores energy in the electric field that forms between its two plates when it is charged. When a voltage is applied, charges accumulate on the plates and create a field in the dielectric; the energy sits in that field, with the amount given by the formula E = 1/2 C V^2. This is a non-chemical form of energy storage, and it allows the capacitor to respond quickly to charging and discharging. In contrast, a carbon pile and a battery store energy chemically. They rely on electrochemical reactions to hold and release energy, not on a separating of charges in an electric field. An ammeter, meanwhile, is just a device for measuring current and does not store energy. So, the component that stores energy primarily in an electric field is the capacitor.

The key idea is how energy is stored. A capacitor stores energy in the electric field that forms between its two plates when it is charged. When a voltage is applied, charges accumulate on the plates and create a field in the dielectric; the energy sits in that field, with the amount given by the formula E = 1/2 C V^2. This is a non-chemical form of energy storage, and it allows the capacitor to respond quickly to charging and discharging.

In contrast, a carbon pile and a battery store energy chemically. They rely on electrochemical reactions to hold and release energy, not on a separating of charges in an electric field. An ammeter, meanwhile, is just a device for measuring current and does not store energy.

So, the component that stores energy primarily in an electric field is the capacitor.