What is the length of the inductor?

[mba444]

Homework Statement

A 0.5533 mH inductor has a length that is
four times its diameter.
If it is wound with 15.4 cm−1 turns per
centimeter, what is its length? Answer in
units of m.

Homework Equations

L= (Uo*pi*r^2*N^2)/(l)
N= n*l
length=4*diameter therefore l= 2*r

The Attempt at a Solution

so i substituted them back in the first equation
length^3= (L*4)/(Uo*pi*n^2)

after solving for length i got 0.61831 meters .. and it turns to be wrong !

i need your help

i have changed the units from cm^-1 to meters^-1


need your help thanks a lot

 

[hage567]

length=4*diameter therefore l= 2*r

Well, there is a problem with this part. The diameter is 2*radius. What you have done is used diameter = 0.5*radius.