Resistivity Equipment Paper Homework Help

Resistivity Equipment Paper Homework Help

 
Purpose The purpose of this activity is to examine how the resistance of a resistor is determined via geometry of



the resistor, and the material which it is made of. Also, to further the student’s understanding of the



difference between resistance, and resistivity.



Theory Ohm’s Law describes the relationship between the resistance R of a wire, the voltage drop across it V,



and the current through the wire I. This is formally given by the equation;



? = ?



?



The resistance of the wire is a function of both the geometry of the wire, and the material that the wire



is composed of. This is formally given by the equation;



? = ? ?



?



Where here L is the length of the wire, A is the cross-section area of the wire (in this simple equation we



are assuming the cross-section area is constant along the entire length of the wire), and ? is the



resistivity of the material the wire is composed of. The SI units of resistivity are Ohms·meters, Ω·m, and



it is a quantification of how difficult it is to move a current through a length of the material. This



equation shows us that resistance is a property of the object, while resistivity is a property of the



material the object is made of. Due to this distinction it is really incorrect to say things like, “Copper has



a low resistance.” Because Copper has a ‘low’ resistivity. If you take a Copper wire and double its length