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

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

I = 15 A, R = 8Ω

∴ Power P = E/t

P = I²Rt/t

∴ P = I²R

P = 15 X 15 X 8

P = 1800 W

Amount of Heat = 1800 W

Chapter 11