(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

Suppose that the magnetic field in some region has the form

B = k z ˆx.

(where k is a constant). Find the force on a square loop of side a, lying in the yz plane

and centered at the origin, if it carries a current I flowing counterclockwise when looking

down the x axis.

2. Relevant equations

Magnetic force=Integral (I X B) dl

3. The attempt at a solution

The force on the two vertical sides of the loop cancel each other out, and we are left with a top force of I(a/2)B= I((a^2)/2)k. The answer is I(a^2)k, meaning that at the bottom horizontal portion of the loop, the magnetic force is upwards. My question is why would it be upwards, given that the magnetic field is out (in the x direction), and the current, traveling counter-clockwise, is to the right at this part? According to the right-hand rule, shouldn't the magnetic force here be downwards?

Thanks!

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# Homework Help: Wire loop in magnetic field

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