Apparent Power (S) equals V × I and is measured in VA. Which option represents Apparent Power?

Apparent Power (S) equals V × I and is measured in VA. Which option represents Apparent Power?

• A. V × I in Watts
• B. V × I in VA
• C. V × I × cos(phi) in VARS
• D. The product of current and resistance

Answer: (B)

Apparent power is defined as the product of the RMS voltage and RMS current, without regard to the phase angle between them. That gives S in volt-ampere (VA). So the expression that matches this definition is V × I in VA. Real power, the actual work done, is VI cos(phi) and is measured in watts, while reactive power is VI sin(phi) in VAR. The other descriptions either mix in the cos(phi) or use the wrong unit, or rely on current and resistance, which isn’t how apparent power is defined.

Apparent power is defined as the product of the RMS voltage and RMS current, without regard to the phase angle between them. That gives S in volt-ampere (VA). So the expression that matches this definition is V × I in VA. Real power, the actual work done, is VI cos(phi) and is measured in watts, while reactive power is VI sin(phi) in VAR. The other descriptions either mix in the cos(phi) or use the wrong unit, or rely on current and resistance, which isn’t how apparent power is defined.