A 4 kW heater is connected to a 220 V source of power. Calculate (i) the electric current passing through the heater. (ii) the resistance of the heater. (iii) the electric energy consumed in 2 hour use of the heater.
Given, P = 4 kW = 4000 W and V = 220 V (i) P = VI or I = PA Hence, I = 4000220 = 18.18 A (ii) V = IR or R = VI R = 22018.18 = 12.1Ω (iii) Energy consumed, E = P × t E = 4000 W × 2h = 8000Wh = 8 kWh = 8 unit.
