What does the dielectric constant represent?

The dielectric constant represents the ratio of a capacitor's capacitance when a dielectric material is present to its capacitance when using air (or vacuum) as the insulating material. This value indicates how well a dielectric material can store electrical energy in an electric field compared to the baseline of air.

When a dielectric is placed in an electric field, it reduces the electric field strength within the capacitor, allowing the capacitor to store more charge at the same voltage compared to when there is no dielectric present. The higher the dielectric constant, the greater the ability of the material to increase capacitance and thus store more energy. This is fundamental in capacitor design and has significant implications for the performance and efficiency of electronic circuits.

In contrast, the other choices refer to different properties. The ability of the dielectric to carry electric current speaks to conductivity, which is not related to the dielectric constant. The maximum voltage a dielectric can withstand relates to its dielectric strength, which defines how much electrical stress the material can handle before failing. The difference between electrical and thermal conductivity describes how well materials conduct electricity and heat, which is also distinctly separate from the concept of dielectric constant.