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.

Answer 1

Rate of heat produced by a device is given by the expression for power as, P= I²R
Where,
Resistance of the electric heater, R= 8 Ω
Current drawn, I = 15 A

P= (15)² x 8 = 1800 J/s

Therefore, heat is produced by the heater at the rate of 1800 J/s.