[amp_mcq option1=”their waveforms are both ac or both dc” option2=”they have the same amplitude and frequency” option3=”their waveforms cross through zero and reach positive and negative peaks at the same time” option4=”All of the above E. None of the above” correct=”option3″]
The correct answer is: C. their waveforms cross through zero and reach positive and negative peaks at the same time.
Current and voltage are said to be in phase when they reach their maximum and minimum values at the same time. This means that the waveforms of the current and voltage are aligned with each other.
Option A is incorrect because the waveforms of the current and voltage can be either AC or DC, but they must still be in phase for the current and voltage to be said to be in phase.
Option B is incorrect because the waveforms of the current and voltage can have different amplitudes and frequencies, but they must still be in phase for the current and voltage to be said to be in phase.
Option D is incorrect because only option C is necessary for the current and voltage to be said to be in phase.
Option E is incorrect because option C is necessary for the current and voltage to be said to be in phase.