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A filament lamp has a resistance of 180 Ω when the current in it is 500mA. What is the power dissipated in the lamp?

Correct answer: A. 45 W

  • A. 45 W
  • B. 90 W
  • C. 290 W
  • D. 360 W

Explanation

First, convert the current to Amperes: I = 500 mA = 0.5 A. Use the power formula P = I²R. P = 0.5 A² × 180 Ω = 0.25 × 180 = 45 W.

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About Current Electricity

Steady current relates charge flow to potential difference, resistance and resistivity, including how temperature changes a conductor's resistance. Sources with internal resistance have terminal voltage below their emf when delivering current, and maximum power output occurs under a specific load condition rather than at zero resistance.

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