Question
Sat July 28, 2012 By:

An electric lamp is marked 100W,220V.It is used for 5 hrs daily. Calculate (i)its rasistance,while glowing.(ii)energy consumed in KWh per day.

Expert Reply
Sat July 28, 2012
(i)
resistance, R = V2/P  (because P= V2/R)
R= (220*220)/100 = 484 ohm
 
(ii)
1 kWh = 3600000J
now for the lamp, energy consumed in a day = (100*24*3600)J
                                                                       = 2.4 kWh
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