Power/Energy

P = E/t       

  • P power in W     
  • E energy in J      
  • t time in s

E = P  t

Example

Calculate the electric energy dissipated in a bulb of 50 W during 24 h.

E = P t

E = (50) (24 * 3600) = 4.32 x 106 J

Remark  : time  in s(seconds) and the energy in J(Joule)

The unit of time can also be : h(our). Then the unity of energy is Wh (Watthour)

E = P t

E = (50)( 24) = 1200 Wh = 1.2 kWh

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