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Does a 5w LED lamp require 5w/per hour to run ? eg. would 200 x 5w LED lamps running for 1 hour would require 1kwhr of electricity. Or is the 5w related to some other time scale ?

user27511
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    No, it requires 5W, independent of time. 200 of them require 1 kW independent of time. So, running 200 for an hour will require 1 kWh. –  Apr 15 '18 at 20:51
  • When my speedometer says I'm going 30 mph, is that 30 mph per hour? – user253751 Apr 16 '18 at 00:18

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Watts (power) is joules (energy) per second (time). A 5W LED lamp running for one hour will therefore consume 5W * 3600s = 18kJ of energy. 1kWh is equal to 3.6MJ.

Ignacio Vazquez-Abrams
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