# magnetic field of a current loop

by B4ssHunter
Tags: current, field, loop, magnetic
 P: 1,197 Magnets don't produce a magnetic field due to electrons being aligned, it's due to the magnetic dipoles being aligned. Magnetisation is defined as the volume density of magnetic dipoles.
P: 178
 Quote by Drakkith Magnetic field lines are not perpendicular to electric field lines, that's the magnetic and electric field vectors in an em wave. I could charge a magnet and have both types of lines come out of it on each end.
yes this has been confusing me , because in real life a magnet can attract an object in a direction parallel to the direction of the magnetic field * if the object is opposite to the north pole for instance , the direction of the magnetic field is so close to being parallel with the direction in which the force is applied to attract the object *
PF Gold
P: 10,794
 Quote by B4ssHunter yes this has been confusing me , because in real life a magnet can attract an object in a direction parallel to the direction of the magnetic field * if the object is opposite to the north pole for instance , the direction of the magnetic field is so close to being parallel with the direction in which the force is applied to attract the object *
P: 178
 Quote by Drakkith What's confusing about it?
that attraction is perpendicular to the magnetic field , but as i mentioned before , at some points the attraction force is very close to being parallel to the magnetic force * like at points facing the north , south pole of the magnet * , so it was confusing for me
HW Helper
Thanks
P: 9,691
 Quote by B4ssHunter i know that a current loop creates some kind of a short bar magnet , but how ?
Ask the opposite: how bar magnets can exist?

The bar magnets are created by atomic current loops. The electrons orbiting around the nuclei are like current loops, so some magnetic momentum can be assigned to the atoms: they behave as small "bar magnets". These interact and align with each other making magnetic domains. These domains can also aligned and you get a piece of magnet.

ehild
P: 1,197
 Quote by B4ssHunter that attraction is perpendicular to the magnetic field , but as i mentioned before , at some points the attraction force is very close to being parallel to the magnetic force * like at points facing the north , south pole of the magnet * , so it was confusing for me
The Lorentz force is indeed perpendicular to the magnetic field, but the magnetic field in the proximity of the pole of a permanent magnet is very inhomogeneous, and any current loop by its nature has a finite dimension.

BxI will therefore point slightly towards or away from the centre of the bar magnet (but always perpendicular to B itself), and it is the vector sum of BxI over the loop itself which will point towards or away from the magnet.

Watch for 5 minutes from 11:56:

P: 178
 Quote by mikeph The Lorentz force is indeed perpendicular to the magnetic field, but the magnetic field in the proximity of the pole of a permanent magnet is very inhomogeneous, and any current loop by its nature has a finite dimension. BxI will therefore point slightly towards or away from the centre of the bar magnet (but always perpendicular to B itself), and it is the vector sum of BxI over the loop itself which will point towards or away from the magnet. Watch for 5 minutes from 11:56: http://www.youtube.com/watch?v=SNDqAuxYOQ8&t=11m56s
wonderful . thanks alot

 Related Discussions Introductory Physics Homework 3 Introductory Physics Homework 0 Introductory Physics Homework 8 Introductory Physics Homework 1 Advanced Physics Homework 1