Elektrische kracht

The product of the current flowing through a conductor and the voltage across it is known as electric power. The SI unit of electric power is the watt.

Consider a potential difference across a conductor. The electrical field in a conductor is directed from higher to lower potentials. Since the change in the potential difference is negative, the electric field can be determined.

If the charge is positive, the electrical field exerts a force on the charge and moves it through the conductor.

The work done on the charge is equal to the product of the electric force and the length at which the force is applied.

The power dissipated by the material in the form of heat and light is equal to the time rate of change of the work.

In a circuit with a resistor, the potential drop across the resistor is dissipated as heat. By recalling Ohm's law, the power dissipated by the resistor can be calculated.

A relationship can be established between power, current, voltage, and resistance for all ohmic devices.