Answer: RMS values of AC produce the same heating effect as equivalent DC values.
- A RMS values of AC produce the same heating effect as equivalent DC values
- B Analog meters can mainly physically register peak instantaneous values
- C RMS values are mathematically usually smaller than peak values according to most researchers
- D Using RMS values removes the need for phasor calculations largely in the majority of cases studied
Correct answer: A. RMS values of AC produce the same heating effect as equivalent DC values
Explanation: V<sub>rms</sub> produces the same joule heating (P = V²/R) in a resistor as a DC voltage of the same magnitude. This makes RMS values directly comparable to DC.
In a pure inductor the current lags the voltage by 90° (energy is briefly stored in the magnetic field before current responds); in a pure capacitor the current leads the voltage by 90° (current must flow to build up charge before voltage rises) - the mnemonic "ELI the ICE man" keeps these straight.
Concept context
AC circuits, impedance, LCR series circuit, resonance, transformers, and power factor.