An electric heater of resistance 8\(\Omega \) draws 15 A from the service mains 2 hours. Calculate the rate at which heat is developed in the heater.

Rate of heat produced by a device is given by the expression for power as, P=\( I_2R \)

Where, Resistance of the electric heater, R= 8 \(\Omega \)

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.