Question

A conducting copper wire has a 2.0mm diametr, a 1.5 length, and a 50 m resistance. What is the resitivity of the wire? What general information would you need to find out in order to answer the question

Answer 1

The formula for calculating the resistance of a conducting wire is:
R = P A* L/A
Where:
R = Resistance = 50
P = Resitivity = ?
L = Length of the the wire = 1.5
A = Cross sectional area of the wire = 2.0
To use this formula to calculate resitivity, we will make P to become the subject of the formula, thus we have:
P = R * A/L
P = 50 * 2/1.5 = 66.67
Therefore the wire resitivity is 66.67 ohm meter.
The general information that one needs to find out in order to answer this question is the relationship among the parameters that are given in the question.