Investigation To Find Resistivity Of A Constanton Wire

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Investigation To Find Resistivity Of A Constanton Wire

Out Line Of The Experiment

I intend to perform an investigation to find the Resistivity of a piece of Constanton wire, by altering certain fundamental variables.

Theory

The Resistivity of a conductor (in this case Constanton wire) is the resistance per meter of material or volume.

Resistivity is normally represented by roe ( P ).

          P = Resistance ( R ) x Area Circle ( A )

                              Length ( l )

Resistance is worked out using the equation;

         R = Voltage (V ) ÷ Current ( I )

               

Volume is worked out by the equation;

         V = l x A

I have used the equation for the area of a circle because the wire is a cylinder shape, so to work out the area of a circle I will use the equation;

         A = Pi ( π ) x Radius Squared ( r2 )

From these equations you can see what the variables of this experiment are; the radius of the area of circle, the voltage across the wire, the length of the wire and current through the wire.

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 By using the equations above I can also re-arrange them to make this equation;

   

         V ÷ I = ( l ÷ A) x P

And from here;

 

          1 ÷ I = ((V  x A) ÷P ) x l

By using this last equation I’m able to plot a graph, from which I can work out the resistivity, as it is part of the gradient (1÷ I against l).

As voltage and the radius of area of the circle are constants, I can alter the length of wire ...

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