A lamp has power 4 W and a resistance of 16 Ω. What is the current when operated at its rated voltage?

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 $24.99Unlock all

Prepare for the Valero Mechanical Aptitude Test with comprehensive study materials. Enhance your skills with flashcards, hints, and detailed explanations. Ace your exam with confidence!

Multiple Choice

A lamp has power 4 W and a resistance of 16 Ω. What is the current when operated at its rated voltage?

Explanation:
Current through a resistor is determined by the relation P = I^2 R. With a power of 4 W and a resistance of 16 Ω, the current is I = sqrt(P/R) = sqrt(4/16) = sqrt(0.25) = 0.5 A. Another way to see it is to find the rated voltage first: V = sqrt(P R) = sqrt(4×16) = 8 V, and then I = V/R = 8/16 = 0.5 A. If the current were 1 A, the power would be 1^2 × 16 = 16 W; with 2 A or 4 A, the power would be 64 W or 256 W, respectively, which doesn’t match the given 4 W. So the current at the rated voltage is 0.5 A.

Current through a resistor is determined by the relation P = I^2 R. With a power of 4 W and a resistance of 16 Ω, the current is I = sqrt(P/R) = sqrt(4/16) = sqrt(0.25) = 0.5 A. Another way to see it is to find the rated voltage first: V = sqrt(P R) = sqrt(4×16) = 8 V, and then I = V/R = 8/16 = 0.5 A. If the current were 1 A, the power would be 1^2 × 16 = 16 W; with 2 A or 4 A, the power would be 64 W or 256 W, respectively, which doesn’t match the given 4 W. So the current at the rated voltage is 0.5 A.

More Multiple Choice Questions
Subscribe

Get the latest from Passetra

You can unsubscribe at any time. Read our privacy policy