A solenoid 10.0 cm in diameter and 77.2 cm long is made from copper wire of diameter 0.100 cm, with very thin insulation. The wire is wound onto a cardboard tube in a single layer, with adjacent turns touching each other. What power must be delivered to the solenoid if it is to produce a field of 8.00 mT at its center?
Alright, I know
B=μnI , I=B/μn
The Attempt at a Solution
I've gotten all these equations, but just cant put them together >_<
n=N/L=772/.772=1000 turns per length
I=B/μn = 8e-3/(μ*1000) = 6.3662A
now just for R,
l=2πrN = 2(3.1415)(.05)(772) = 242.53
A=π*radius(wire)^2= (3.1415)(.0005)^2 = 7.854e-7
So, P = RI^2 = 5.25*6.3662^2 = 212.77W !!