What is the opposition to direct current (DC) called?

Resistance refers to the opposition to the flow of electric current in a circuit. It's a fundamental concept in electrical engineering and corresponds to how much a material opposes the movement of electrons when a potential difference is applied. In the case of direct current (DC), resistance is the primary factor that prevents the flow of electricity through a conductor.

The unit of resistance is ohms, and it can be influenced by various factors like the material of the conductor, its length, and its cross-sectional area. Understanding resistance is crucial in designing circuits, as it affects how much current will flow for a given voltage, according to Ohm's Law.

Impedance, while also related to opposition to current flow, encompasses more than just resistance; it includes both resistance and reactance (from capacitive and inductive components). Therefore, while the term impedance applies to AC circuits, resistance specifically describes the opposition in a DC context.