# Question regarding force on a square loop due to a magnetic field

1. Jul 26, 2008

### soumyasch

I am really stuck on this question, can someone help me out?

Code (Text):
Suppose that the magnetic field in some region has the form [B]$$\vec{B}$$[/B]=kz$$\hat{x}$$ where [I]k[/I] is a constant. What is the force it will exert on a square loop of side [I]a[/I], lying in the [I]yz[/I]-plane and centered at the origin. The loop carries a current [I]I[/I] that flows conterclockwise looking down the [I]x[/I]-axis.
It would be very helpful if the steps that should be followed to solve this problem could be provided. Solution is not solicited. Thanks in advance.

2. Jul 26, 2008

### Defennder

What have you done regarding this? What formula should you use here?

3. Jul 27, 2008

### soumyasch

This is not a assignment or homework of mine :) I have been out of touch with electromagnetics for about six years now. But recently I am having a need to refresh what I learnt in my first year of graduation. Instead of reading through textbooks all over again, I am trying to go through solutions of problems trying to recall something.

Like I already said, I don't remember much from my graduation course (I am a CSE graduate) (and definitely not names of formulae) and where they are applied. I would be very grateful if someone can guide me on what formulae needs to be applied here (I don't want the solution) so that by doing this a few times I get enough confidence to try a few other problems on my own. Thanks.

4. Jul 27, 2008

### Staff: Mentor

The force on an element of current in a magnetic field is given by:
$$I d\vec{\ell} \times \vec{B}$$