The ohm () is the unit used to measure the electrical resistance of a circuit. The amount of opposition that a conductor offers to the movement of electric current is measured in units called ohms. It is defined as the ratio of the voltage that is provided to a conductor to the current that is subsequently flowing through the conductor as a result of the application of the voltage.

A current of one ampere will flow through a conductor, for instance, if a voltage of one volt is supplied to the conductor and it has a resistance of one ohm. Ohm’s Law is a statement that describes the relationship between voltage, current, and resistance. It states that the current that is flowing through a conductor is directly proportional to the voltage that is being applied to the conductor and that this current is inversely proportional to the resistance that is being presented by the conductor.

The “opposition” that a conductor presents to the movement of electric current is one way to conceptualise the phenomenon known as electrical resistance. Copper and other materials with low electrical resistance are considered to be good conductors of electricity and are thus utilised in the construction of electrical cables and other electrical components. Insulators are made out of substances that are poor electrical conductors and have high resistance, such as rubber. Insulators are utilised in the electrical industry.