Final answer:
The correct equation for apparent power (S) is S = √(P2 + Q2). Apparent power, measured in volt-amperes (VA), combines real power (P) and reactive power (Q) to represent the total power in an AC circuit.
Step-by-step explanation:
The correct equation for apparent power (S) based on real power (P) and reactive power (Q) is S = √(P2 + Q2), which comes from the Pythagorean theorem applied in the context of the power triangle. This triangle represents the relationship between the different types of power in an alternating current (AC) circuit. Real power (P) is measured in watts (W) and represents the power actually used by the load to perform work. Reactive power (Q), measured in volt-amperes reactive (VAR), represents the power that oscillates back and forth between the source and the load, not doing any work but is necessary for the functioning of some equipment like motors and transformers.
It is important to note that apparent power is the vector sum of real and reactive power and is measured in volt-amperes (VA). Conservation of energy in an electrical circuit dictates that the power output from the source must be equal to the total power dissipated by the resistors.
To see the relationship of power to resistance, we use Ohm's law and different expressions for electric power, such as P = IV, P = V2/R, and P = I2R. These expressions show the intricacy of how voltage, resistance, and current are interconnected in determining the power within an electrical circuit.