Resistance Of A Wire - page 5
Keywords: Resistance Of A Wire
By RyanJK on 07/11/2006 17:49:43
Level: GCSE Key Stage 4 (Years 10-11)
Page Number: 5 of 5 pages: 1 2 3 4 5
to this would be to, before each experiment, connect the connections together without the wire in place and measure the resistance then. If it is higher than it should be then the connections could be cleaned.
Whilst extremely unlikely, it is conceivable that the power supply was providing a different voltage for some of the results. This is unlikely to be a problem in this investigation as I made sure the voltage stayed at 1volt, but it might have been an issue had we used batteries instead.
If one were to assume that Ohm’s Law applies, then another possible explanation could be that at some points (more likely in the lower lengths), the wire was not allowed to cool completely so that the temperature was higher for that measurement. Whilst, this would cause a higher resistance as explained previously. However, it is now known, after researching the metal alloy “constantan,” that the resistivity (the electrical resistance of a conductor of particular area and length) of this alloy is not affected by temperature. Therefore, in these experiments Ohm’s Law does not apply.
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