Resistors in series

Two resistors, R1 and R2 , were conected in series across a baterry, the current being indicated by an ammeter A. Also, voltmeters V1, V2 and V3 were conected to measure the voltages across R1, R2 ad the whole circuit respectively. The following readings were obtained : A = 0.92 ampere. V1 = 2.2 volts. V2 = 3.6 volts. V3 = 5.8 volts

By applying Ohm’s law, we find that

            R1 = 2.2/0.92 = 2.39 Ω

            R2 = 3.6/0.92 = 3.91 Ω

And the resistance of the whole circuit

             5.8/0.92 = 6.30 Ω

The sum of R1 and R2

            = 2.39 + 3.91 = 6.30 Ω

Heance it is seen that the total resistence of a circuit is the sum of the resistances in series ; in other words, if resistors R1, R2 and R3 be in series, the ttal resistance R is given by

R = R1 + R2 + R3

Also, if the voltmeters are of moving-coil type, V1 and V2 indicate that L is at a higher potential than M and that M is at a higher potential than N ; and V3 indicates that L is at a higher potential than N by an amuont aqual to the sum of the potential differences LM and MN.