Final answer:
The power factor equation that relates true power and apparent power is A) Power factor = True power / Apparent power. It's a measure of an electrical system's efficiency and indicates how much power is used for work versus lost as reactive power.
Step-by-step explanation:
In Physics, specifically in the context of electrical circuits, the correct power factor equation relating true power and apparent power is: Power factor = True power / Apparent power. This means the correct answer from the options provided is A) Power factor = True power / Apparent power.
The power factor is a dimensionless number between 0 and 1, which represents the efficiency with which an electrical system converts electrical power to useful work output. The term cos refers to the cosine of the phase difference between the current and voltage. When the power factor is near 1, the system is considered efficient, as more of the power is being used for useful work, which is typically the case for a well-designed motor or an electrical system operating at its resonant frequency.
An understanding of the power factor is crucial in engineering applications, as it affects the energy consumption and overall efficiency of electrical systems. In practice, a power factor closer to 1 indicates that less energy is lost in the form of reactive power and more is utilized as true (real) power.