Final answer:
A dielectric is an insulating material that can become polarized within an electric field. The dielectric strength is the maximum electric field the material can handle before it conducts. The dielectric constant is a measure of a material's ability to reduce the electric field within it, and affects the capacitance of capacitors.
Step-by-step explanation:
Dielectric Materials
A dielectric is an electrically insulating material that can become polarized when it is placed in an electric field. Polarization occurs when the electrons within the material move slightly with respect to their nuclei, creating small internal electric dipoles in response to the external field. However, the material remains an insulator because the electrons do not have enough energy to break free from their atoms completely.
Dielectric Strength
The term dielectric strength refers to the maximum electric field that a dielectric material can withstand without undergoing electrical breakdown. When an insulating material's dielectric strength is exceeded, it begins to conduct because the molecules within the material become ionized.
Dielectric Constant
The dielectric constant (often represented as k) of a material is the ratio of the electric field in a vacuum (Eo) to the net electric field within the material (E). It reflects the material's ability to reduce the electric field inside it, which is related to its polarizability. This characteristic is crucial for a capacitor, as a capacitor filled with a dielectric has a larger capacitance than an empty one, meaning it can store more electrical energy.