 # A hot plate of an electric oven connected to a 220 V line has two resistance coils A and B, each of 24 resistances, which may be used separately, in series, or in parallel. What are the currents in the three cases?

Supply voltage, V= 220 V Resistance of one coil, R= 24 Î© (i) Coils are used separately According to Ohm’s law, V= I1R1 Where, I1 is the current flowing through the coil I1 = V/R1 = 220/24 = 9.166 A Therefore, 9.16 A current will flow through the coil when used separately. (ii) Coils are connected in series Total resistance, R2 = 24 Î© + 24 Î© = 48 Î© According to Ohm’s law,V = I2R2 Where, I2 is the current flowing through the series circuit I2 = V/R2 = 220/48 = 4.58 A Therefore, 4.58 A current will flow through the circuit when the coils are connected in series. (iii) Coils are connected in parallel Total resistance, R3 is given as = According to Ohm’s law, V= I3R3 Where, I3 is the current flowing through the circuit I3 = V/R3 = 220/12 = 18.33 A Therefore, 18.33 A current will flow through the circuit when coils are connected in parallel.