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Question
An electric heater of resistance 8 Ω draws 15 A from the service mains 2 hours. Calculate the rate at which heat is developed in the heater.
Solution
Resistance of the electric heater, R = 8 Ω
Current I = 15 A
Time, t = 2 hr.
Rate of generation of heat = I2 × R
= (15)2 × 8
= 255 × 8
= 1800 W
Therefore, heat is produced by the heater at a rate of 1800 W.
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