A 10 W lamp operates continuously for one minute. How much energy (in joules) does it dissipate during that time interval?

Difficulty: Easy

Correct Answer: 600 joules

Explanation:


Introduction / Context:
Power quantifies the rate at which energy is used or converted, while energy measures the total amount consumed over time. Converting between power (watts) and energy (joules) is a fundamental calculation in electrical engineering and physics.


Given Data / Assumptions:

  • Lamp power P = 10 W (that is, 10 joules per second).
  • Operating time t = 1 minute = 60 seconds.
  • Assume constant power during the interval.


Concept / Approach:
Energy E is the time integral of power. For constant power, E = P * t. Units: 1 W = 1 J/s, so multiplying by seconds gives joules directly. This simple relation underpins energy billing (e.g., kilowatt-hours) and battery capacity calculations when adapted to appropriate units.


Step-by-Step Solution:
Identify P = 10 W and t = 60 s.Compute energy: E = P * t = 10 * 60 = 600 J.Therefore, the lamp dissipates 600 joules in one minute.


Verification / Alternative check:
Convert to watt-hours for intuition: 10 W for 1 minute is (10 W) * (1/60 h) = 0.1667 Wh. Convert Wh to joules using 1 Wh = 3600 J → 0.1667 * 3600 ≈ 600 J, confirming the result.


Why Other Options Are Wrong:

  • 10 joules: That would be the energy after only 1 second at 10 W.
  • 60 joules: Corresponds to 10 W for 6 seconds.
  • 3600 joules: That would be 10 W for 360 seconds (6 minutes) or 1 W for 1 hour.


Common Pitfalls:

  • Mistaking minutes for seconds; always convert time to seconds when using SI units.
  • Confusing power (rate) with energy (total amount).


Final Answer:
600 joules

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