Which of the following is NOT a formula for Power Factor?

The correct answer identifies an expression that does not represent the formula for Power Factor. Power Factor is fundamentally defined as the cosine of the phase angle (indicating the phase relationship between current and voltage in an AC circuit), the ratio of Real Power to Apparent Power, or derived from the power equation involving voltage and current.

In options related to Power Factor formulas:

1. The cosine of the phase angle accurately captures the Power Factor in terms of the angle between the current and voltage waveforms, emphasizing the importance of power flow efficiency.

2. The ratio of Real Power (watts) to Apparent Power (volt-amperes, VA) effectively expresses the Power Factor mathematically, illustrating how much of the electrical power is utilized versus what is supplied.

3. The relationship of watts divided by the product of voltage and current also leads to the definition of Power Factor since voltage multiplied by current provides Apparent Power in the circuit.

In contrast, the expression involving Current divided by Voltage does not represent Power Factor. Instead, it expresses a relationship concerning current and voltage but lacks the necessary context of real versus apparent power or the phase angle, which are essential in defining Power Factor.