In electrical terms, what does the letter E denote in the formula P = EI?

In the formula P = EI, the letter E represents Voltage. This formula relates power (P) to voltage (E) and current (I), indicating that electrical power can be calculated by multiplying the voltage by the current flowing through a circuit.

Understanding voltage is crucial in the context of electrical systems, as it is the measure of electrical potential difference between two points. Voltage drives the flow of electrons through a conductor, thereby enabling electrical devices to function.

The other options represent different concepts in electrical theory. 'Energy' refers to the capacity to do work and has different units. 'Electrons' refer to the fundamental particles that carry electrical charge but are not directly represented in this formula. 'Efficiency' measures how well a system converts input energy to output energy but is unrelated to the specific relationship between power, voltage, and current described in this equation.