- #1
Angie K.
- 108
- 1
Homework Statement
A coil of fine copper wire has a resistance of 6.2 -Ω and a total mass is 14.4 g. What is the diameter d of the wire and what is its length L? (The density of copper is 8.96 g/cm3.)
Hint Given: •Model the wire as a long cylinder of diameter d and length L. Write one relation for its mass, another for its resistance--from these two relations, you can determine the two desired quantities.
Homework Equations
R=p*L/A where R = Resistance, p = resistivity coefficient, L = length, A = Area
In this case resistivity coefficient of copper is given as p = 1.68*10^-8 Ohms/m
The Attempt at a Solution
Using the equation R=p*L/A I know the value of R is 6.2 Ohms and the value of p is 1.68*10^-8 Ohms/m
I know that to find the diameter and length of the cylinder, I need to find the Area.
To find the area, my method is: p/R * L = A
But I only know p and R, so I'm not sure how to solve for the length and the area.
Would I just use v = m/d where v = volume and m/d = mass/density ?
If I do that:
(14.4g)/(8.96g/cm^3) = 1.607142 (volume)
What do I do once I get the volume? Do I convert the volume measurements since they're in cm^3?
Maybe this is more of a math question but I'm just stuck at that part so I would appreciate some help.