Subelement A: — Topic :
Question 6A525
Element 6 (Radiotelegraph)The product of the readings of an AC voltmeter and ammeter in an AC circuit is called what?
Explanation
In an AC circuit, an AC voltmeter measures the Root Mean Square (RMS) voltage, and an AC ammeter measures the RMS current. The mathematical product of these two readings (V_RMS × I_RMS) is defined as **apparent power**. This value represents the total power that *appears* to be delivered by the source and is measured in Volt-Amperes (VA).
It is called "apparent" because it does not account for the phase difference that can exist between the voltage and current waveforms in circuits containing reactive components (inductors or capacitors). Only the portion of apparent power that is "in phase" with the voltage actually performs work and is known as "real power" or "true power," measured in Watts.
Option A, "Reverse power," refers to power flowing back towards the source, which is a different concept. Option C, "Current power," is not a standard electrical term. Therefore, apparent power (B) is the correct term for the product of AC voltage and current readings.
Related Questions
6A523 Why are copper oxide rectifiers, associated with DC voltmeters to measure AC, unsuitable for themeasurement of voltages at radio frequencies?6A524 How may the power in a AC circuit be determined?6A526 Does an AC ammeter indicate peak, average, or effective values of current?6A527 What types of meters may be used to measure RF currents?6A528 How may the range of a thermocouple ammeter be increased?