In this laboratory experiment, you will measure the resistivity (ρ) of a Copper and Nickel wire.
Equipment:
FiveCenco coils mounted on a base (see the wire diameter printed in the base), Ammeter, Voltmeter, leads, power supply, Rheostat (30 Ω), Single throw switch (S).
Theory:
Resistivity (ρ) in Ohmm, length (L) in m, Resistance (R) in Ohms.
_{}
Procedure:
Connect the circuit as shown. Keep the power supply off until your instructor checks your circuit. Power supply voltage should be around 5.00 V, and the rheostat’s adjustable slide at the middle. Current can be changed the by moving the sliding conductor on the rheostat while keeping the voltage constant. Fill in the following information from the setup, and the table from your measurements.
Coil #________Diameter (in)_________Length (m)____________

Voltage (V) 
Current I (A) 
R = V/I 
1 



2 



3 



4 



5 



6 



Reproduce this table on your paper as need for other wires.
Spreadsheet Work:
Use a spreadsheet like excel to find the slope from linear regression. To do this on excel, enter your voltage (Volt) in the second column and your current (A) in the second column in an excel session. Highlight both data by dragging the mouse across the data cells while right button is held down. From the top menu bar, choose graph icon. Select XY scatter graph, and finish it after going through the suggested steps. Once you obtained the graph, click anywhere on the graph area. Choose chart from menu bar, and click on “add trendline”. From the options bar check “show equation” and “R value” (this is not Resistance).
Report the followings:
1) Slope of the equation is the resistance R of the wire.
2) Accepted value of the resistivity ρ for the wire.
3) Resistivity. Use the slope (R) to calculate the resistivity ρ of the copper and compare with the book value.
4) Calculate the percentage error as usual (see previous handout for formula). Report all of these results in your labreport. Reports are due one week after the lab work.
Write a conclusion. See the lab writeup format on the net (www.utm.edu/~cerkal/cahit.htm): if this site doesn’t work probably need to add an l at the end (…../cahit.html) or start from Geology, Geography and Physics home page.