What is the formula for Apparent Power (S) in an AC circuit?

The formula for Apparent Power (S) in an AC circuit is represented as the product of the voltage (Vt) and the current (It). Apparent Power is measured in volt-amperes (VA) and reflects the total power flowing in the circuit, regardless of whether it is being used effectively (as in the case of real power) or is wasted (as in reactive power). This relationship highlights the fundamental principle that in alternating current (AC) systems, power is a function of both the voltage across the components and the current flowing through them.

In this context, Vt represents the RMS (root mean square) voltage, and It signifies the RMS current. When multiplied together (S = Vt * It), this gives a complete measure of the power in the system, which is crucial for understanding AC circuit behavior.

The other options suggest different mathematical relationships that do not accurately compute Apparent Power. The addition, division, or cosine function do not capture the essence of how voltage and current combine to quantify power in alternating current systems. Thus, multiplying the RMS voltage by the RMS current is the correct and established formula for calculating Apparent Power.