Asked by Mary
A piece of copper wire has a resistance per unit length of 5.95 10-3 /m. The wire is wound into a thin, flat coil of many turns that has a radius of 0.200 m. The ends of the wire are connected to a 12.0 V battery. Find the magnetic field strength at the center of the coil.
In this question do I use the following formula:
F = /q0/v(permeability of free space x I / 2piR) sin theta
In this question do I use the following formula:
F = /q0/v(permeability of free space x I / 2piR) sin theta
Answers
Answered by
drwls
The field at the center is proportional to the number of turns, N, but the current is inversely proportional to then number of turns (because increasing N increases the resistance). Therefore N cancels out.
B = mu*N I /(2r)
(For a reference to that formula, see (Broken Link Removed)
r is the loop radius; R is the total resistance of all N turns
I = V/R
R = (resistance per length)* 2 N pi r
I = V/((resistance per length)* 2 N pi r)
B = mu*V/((resistance per length)* 4 pi r^2)
B = mu*N I /(2r)
(For a reference to that formula, see (Broken Link Removed)
r is the loop radius; R is the total resistance of all N turns
I = V/R
R = (resistance per length)* 2 N pi r
I = V/((resistance per length)* 2 N pi r)
B = mu*V/((resistance per length)* 4 pi r^2)