In a DC circuit, the ratio of Watts to Volt-Amperes is always?

Unlock all questions

This demo includes only 20 questions. Upgrade to access hundreds of questions, flashcards, exam simulations, and disable ads.

Full question bankExam simulationsFlashcards
From $25.99Unlock all

Prepare for the New York City Electrician Test. Study with flashcards and multiple choice questions, each question has hints and explanations. Get ready for your exam!

Multiple Choice

In a DC circuit, the ratio of Watts to Volt-Amperes is always?

Explanation:
In a DC circuit, real power (watts) and apparent power (volt-amperes) are the same because voltage and current are in phase with no reactive component. With no phase difference, the power that actually does useful work equals the product of voltage and current, so P = V × I. Apparent power is also V × I in DC, so the ratio P / S is exactly 1. That unity ratio is what makes the answer unity every time. In contrast, in AC circuits with any reactance, the ratio would be less than 1 depending on the power factor, but not greater than 1.

In a DC circuit, real power (watts) and apparent power (volt-amperes) are the same because voltage and current are in phase with no reactive component. With no phase difference, the power that actually does useful work equals the product of voltage and current, so P = V × I. Apparent power is also V × I in DC, so the ratio P / S is exactly 1. That unity ratio is what makes the answer unity every time. In contrast, in AC circuits with any reactance, the ratio would be less than 1 depending on the power factor, but not greater than 1.

More Multiple Choice Questions
Subscribe

Get the latest from Passetra

You can unsubscribe at any time. Read our privacy policy