alleryStart learning →An older incandescent light bulb is rated at 60 W and operates at 120 V. What current flows through it?
A2.0 amp
B0.50 amp
C7200 amp
D0.0083 amp
Answer & Solution
Correct answer: B. 0.50 amp
1. Electric power is P = IV, so I = P/V.
2. Substitute P = 60 W and V = 120 V.
3. I = 60 W / 120 V = 0.50 A.
4. 2.0 A would result from dividing voltage by power instead of power by voltage.
_Source: OpenStax Physics (CC BY 4.0), Ch 19 "Electrical Circuits", section Find the Resistance of a Lightbulb_
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