An electric heater which is connected to a 220V supply line has two resistance coils A and B of 24 ohm resistance each. These coils can be used separately in series or in parallel. Calculate the current drawn when: a) only one coil A is used b) coils A and B are used in series coils A and B are used in parallel

Given, V = 220V Ra = Rb = 24 ohm a) Current drawn when only coil A is used: I = V/Ra = 220/24 = 9.16 amps b) Current drawn when the coils A and B are used in series: Total resistance, R = Ra + Rb = 24 + 24 = 48 ohms I = V/R = 220/48 = 4.58 amps c) Current drawn when coils A and B are used in parallel: Total resistance is 1/R = 1/Ra + 1/Rb = 1/24 + 1/24 = 2/24 = 1/12 R = 12 ohms I = V/R = 220/12 = 18.33 amps