What is the Optimal Diameter for a 12.0 Ω Nichrome Wire at 20°C?

[phy112]

Homework Statement

If 46 m of nichrome wire is to have a resistance of 12.0 Ω at 20°C, what diameter wire should be used?

Homework Equations

R=$$\rho$$(L/A)

The Attempt at a Solution

I tried and I got 2.1. The $$\rho$$ of nichrome is 108e-8

 

[Mr.Amin]

First solve for the variable you are looking for and put it on one side. Keep your knowns on the other side. Remember that A stands for area, and area is related to wire diameter.

I am online for a bit, so give it a go. DON'T FORGET YOU UNITS!

 

[phy112]

ok yeah i got 2.3 mm. after i figured out A. I figured out diameter doing A=1/4pi(dsquared)

 

[phy112]

ok i got it right. thanks!

 

[Mr.Amin]

Good for you!