Power in Circuits Video Lessons

Concept

Problem: A 100 W lightbulb is brighter than a 60 W lightbulb when both operate at the same voltage of 120 V. If, instead, they were both operated at the same current of 0.5 A, which would be brighter? Select the correct answer and explanation.A. The 60 W bulb has higher resistance, so it would be brighter.B. The 60 W bulb has lower resistance, so it would be brighter.C. The 100 W bulb has higher resistance, so it would be brighter.D. The 100 W bulb has lower resistance, so it would be brighter.

FREE Expert Solution

Power in circuits:

$\overline{){\mathbf{P}}{\mathbf{=}}{\mathbf{V}}{\mathbf{i}}{\mathbf{=}}{{\mathbf{i}}}^{{\mathbf{2}}}{\mathbf{R}}{\mathbf{=}}\frac{{\mathbf{V}}^{\mathbf{2}}}{\mathbf{R}}}$

We'll determine the resistance of the bulbs, then use the expression P = i2R.

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Problem Details

A 100 W lightbulb is brighter than a 60 W lightbulb when both operate at the same voltage of 120 V. If, instead, they were both operated at the same current of 0.5 A, which would be brighter? Select the correct answer and explanation.

A. The 60 W bulb has higher resistance, so it would be brighter.

B. The 60 W bulb has lower resistance, so it would be brighter.

C. The 100 W bulb has higher resistance, so it would be brighter.

D. The 100 W bulb has lower resistance, so it would be brighter.