What is placed between the two conducting plates of a capacitor to increase its storage?

What is placed between the two conducting plates of a capacitor to increase its storage?

• A. Vacuum
• B. Conductor
• C. Dielectric
• D. Air

Answer: (C)

Inserting a dielectric between the plates increases storage by boosting the capacitor’s capacitance. A dielectric is an insulating material that becomes polarized in an electric field, creating bound charges that oppose the field. This reduces the effective field for a given amount of charge, so more charge can be stored at the same voltage. For a parallel-plate capacitor, the capacitance becomes C = κ ε0 A / d, where κ is the dielectric constant of the material between the plates. A material with a higher κ increases capacitance, meaning more charge can be stored for the same voltage. A conductor between the plates would create a short circuit and prevent charging. Air or vacuum act as dielectrics with κ close to 1, so they don’t increase storage much beyond a vacuum.

Inserting a dielectric between the plates increases storage by boosting the capacitor’s capacitance. A dielectric is an insulating material that becomes polarized in an electric field, creating bound charges that oppose the field. This reduces the effective field for a given amount of charge, so more charge can be stored at the same voltage. For a parallel-plate capacitor, the capacitance becomes C = κ ε0 A / d, where κ is the dielectric constant of the material between the plates. A material with a higher κ increases capacitance, meaning more charge can be stored for the same voltage. A conductor between the plates would create a short circuit and prevent charging. Air or vacuum act as dielectrics with κ close to 1, so they don’t increase storage much beyond a vacuum.