The purpose of this experiment was to verify the principle that the resistance of a conductor is directly proportional to its length by using Ohmâ€™s law.
From the tabulated results and the graph, it can be seen that there is a linear relationship between the resistance of the conductor and its length. Therefore, ohms law is correctly proven.
Errors might have been introduced by the contacts between the crocodile clips and the wire, which may have introduced extra resistance into the circuit. The amount of extra resistance cannot be estimated and may have changed during the course of the investigation.
Constantan wire was selected for the investigation because its resistance does not change very much as the temperature changes. However, in cases where it is not available it should be possible to a technique for connecting the wires into the circuit, which would eliminate any uncertainty due to the contacts