Equivalent Resistance of Resistors (Series)

An electric circuit is simply a closed loop through which charges can continuously move. An electric circuit basically contains a source of electricity, a load resistance, a switch or a key for turning the circuit on or off at one’s convenience. When two or more resistors are connected such a way that one end of one resistor is connected to the starting end of the other, then the circuit is called a Series Circuit. Since the current has only one path to take, the current through a series circuit is the same through each resistor. The total resistance/effective resistance of the circuit is found by simply adding up the resistance values of the individual resistors. Adding resistors in series always increases the effective resistance. ie., If Rs be the resistance of the series combination then, Rs = R1 + R2+ R3 +…………

This video explains how to determine the resistance per cm of a given wire by plotting a graph of potential difference versus current.