How much energy is consumed when a current of 5 amperes flows through the filament (or element) of a heater having resistance of 100 ohms for two hours ? Express it in joules. 

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1 Answers

I=5amp, R=100ohms, t=2h

 We know that

Electric energy consumed = P x t = I x I x Rt = 25 x 100 x 2 = 5000 Wh = 5 kwh

We know that 1kwh = 3.6 x 106 J

Therefore, 5kwh = 5 x 3.6 x 106 J = 18 x 106 J.

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