With the help of a circuit diagram, deduce the equivalent resistance of two resistances connected in series.
Let the current in the circuit be I amperes and the battery be of strength V volts. Let the combined resistance of the three resistors be R ohms.
Therefore, according to Ohm's law, we have
V=IR ---- (i)
We know that when resistors are connected in series, the current with a battery of V volts.
V1=I×R1 ------- (ii)
V2 =I×R2 ------ (iii)
Let the potential difference across R1 is V1 and the potential difference across R2 is V2
V=V1+V2--------- (iv)
From equation (i),(ii), (iii) and (iv) we get.
IR= I×R1+ I×R2
R= R1+ R2
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