Question 343: AC fundamentals

Question

What will be the phase difference between virtual voltage and virtual current when current in the circuit is wattless?

Accepted Answer

When the current in an AC circuit is described as "wattless," it means that the current does not do any real work. This happens when the current and the voltage are out of phase by $$90^{\circ}$$. In such a situation, the power factor of the circuit is zero, as power factor is defined as the cosine of the phase angle between the voltage and the current, given by:
$$ 	ext{Power Factor} = \cos(\phi) $$
where $$\phi$$ is the phase difference. If the power is wattless, then:
$$ 	ext{Power Factor} = \cos(90^{\circ}) = 0 $$
The phase difference that makes the cosine equal to zero is $$90^{\circ}$$ since:
$$ \cos(90^{\circ}) = 0 $$
Therefore, the correct answer is Option C: $$90^{\circ}$$. This phase difference implies that when the voltage reaches its peak value, the current is zero, and vice versa, meaning the voltage and current waves are out of phase by a quarter cycle.

Answer

$$60^{\circ}$$

Answer

$$45^{\circ}$$

Answer

$$90^{\circ}$$

Answer

$$180^{\circ}$$

AC fundamentals

What will be the phase difference between virtual voltage and virtual current when current in the circuit is wattless?

Choose the correct answer: