alleryStart learning →A resistor of 100 ohm is connected across a 12 V source. What electric power is dissipated in the resistor?
A1.4 W
B0.12 W
C144 W
D12 W
Answer & Solution
Correct answer: A. 1.4 W
1. First find the current using Ohm's law: I = V/R = 12 V / 100 ohm = 0.12 A.
2. Electric power is P = IV.
3. Substitute the values: P = (0.12 A)(12 V) = 1.4 W.
4. 144 W would result from multiplying voltage by itself instead of by the current.
_Source: OpenStax Physics (CC BY 4.0), Ch 19 "Electrical Circuits", section 19.4 Electric Power_
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