Which term describes an insulating material that stores energy in an electrostatic field?

Which term describes an insulating material that stores energy in an electrostatic field?

• A. Dielectric
• B. Shorted Resistors
• C. Inductors
• D. Calculation of Capacitive Reactance

Answer: (A)

An insulating material that stores energy in an electrostatic field is called a dielectric. When placed between the plates of a capacitor, the dielectric becomes polarized in the presence of the electric field. This polarization reduces the effective field for a given voltage and allows more charge to be stored, which increases the capacitance. The stored energy is in the electric field, described by u = 1/2 C V^2, and the capacitance scales with the dielectric’s permittivity: C = ε_r ε_0 A / d. This insulating property prevents DC current flow while still supporting an electric field and energy storage. Shorted resistors don’t store energy in a field; they conduct and dissipate energy as heat. Inductors store energy in a magnetic field, not an electrostatic one. Calculations of capacitive reactance are circuit formulas, not a material.

An insulating material that stores energy in an electrostatic field is called a dielectric. When placed between the plates of a capacitor, the dielectric becomes polarized in the presence of the electric field. This polarization reduces the effective field for a given voltage and allows more charge to be stored, which increases the capacitance. The stored energy is in the electric field, described by u = 1/2 C V^2, and the capacitance scales with the dielectric’s permittivity: C = ε_r ε_0 A / d. This insulating property prevents DC current flow while still supporting an electric field and energy storage.

Shorted resistors don’t store energy in a field; they conduct and dissipate energy as heat. Inductors store energy in a magnetic field, not an electrostatic one. Calculations of capacitive reactance are circuit formulas, not a material.