Which materials are known to restrict the flow of electric charges?

Insulators are materials that are highly resistant to the flow of electric charges, making them crucial in electrical engineering and applications where safety and control of electric currents are necessary. Common examples of insulators include rubber, glass, and certain plastics. These materials possess very few free electrons, which means that when a voltage is applied, the electric charges cannot move freely through the material. Instead, insulators effectively prevent the flow of electric current, serving to protect and isolate components within electrical circuits.

In contrast, conductors allow for easy flow of electric charges due to a high density of free electrons, which are readily available to carry the current. Capacitors store electrical energy and aren’t designed specifically to restrict charge flow, while semiconductors have conductive properties that can vary depending on conditions such as temperature and the presence of impurities, thus they don’t inherently restrict charge flow like insulators do.