The power rating of a light bulb (such as a 100-W bulb) is the power it dissipates when connected across a 120-V potential difference. (a) What is the resistance of a 100-W bulb? ? (b) What is the resistance of a 75-W bulb? ? (c) How much current does each bulb draw in normal use? I???-? = A I??-? = A
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We can rearrange this formula to solve for R: R = V^2/P. Plugging in the given values, we get R = (120 V)^2 / 100 W = 14400 W / 100 W = 144 Ω. So, the resistance of a 100-W bulb is 144 ohms. Show more…
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