A sample of copper wire is housed within an electrical insulated glass chamber. The temperature is periodically cycled between $30\backslash$deg C and $50\backslash$deg C$.$ The resistance of the copper is measured automatically every second.

Copper wire specification

Length $61$ m $(+/-0\mathrm{.}4$ m$)$

Diameter $140$ microns $(+/-5$ micron$)$

You will record the time, temperature, resistance of the experiment for atleast one complete cycle of heating and cooling.

One cycle should take approximately $40$ minutes, the exact cycle time being dependant upon ambient conditions. The time of the previous cycle is shown in seconds to give a better estimate of current cycle times. When the cycle is in the heating phase a red lamp is lit, and when the cycle is in the cooling phase a blue lamp is lit. The fan is used to help to cool the glass chamber and its contents more quickly.

It is necessary to take the experiment off line once per week to test equipment safety systems. This will be between $15$:$00-17$:$00$ local time each friday. There is currently no sound assosiated with the experiment.

The temperature coefficient, $($a$),$ describes the rate of change of material property as a function of temperature. Resistivity, $($p$),$ will vary with temperature according to the following equation:

p$($T$)=$p$($T$)(1+$a$\backslash$geotriangle T$)$

Where $($T$)$ is the temperature, T$$ is the internal temperature, and $\backslash$geotriangle T is the difference between T and T$.$

In this experiment take T$$ to be $30\backslash$deg C$.$

$1-$Take readings of the resistance of the wire between $30\backslash$deg C a d $50\backslash$deg C and calculate the resistivity of the wire at each recorded temperature. You will need sufficient data points to allow you to plot a graph.

$2-$Plot these data points on a scatter graph with resistivity on the y axis and temperature difference $\backslash$geotriangle T on the x axis.

$3-$Estimate the temperature coefficient, $($a$),($units k$-),$ for the resistivity of the copper wire between $30\backslash$deg C$-50\backslash$deg C$.$

$4-$Compare the value obtained in step $3$ with literature value $*$ of $0\mathrm{.}00404$ k$-.$

$5-$If there is a discrepancy between the measured and literature values, consider how you think this might arise.