# Force on loop of wire pulled through magnetic field

1. Apr 20, 2010

### brianfast

1. The problem statement, all variables and given/known data

1.A loop of wire is pulled with constant velocity v to the right through a region of space where there is a uniform magnetic field B directed into the page, as shown above. The magnetic force on the loop is
a.Directed to the left both as it enters and as it leaves the region
b.Directed to the right both as it enters and as it leaves the region
c.Directed to the left as it enters the region and to the right as it leaves
d.Directed to the right as it enters the region and to the left as it leaves
e.Zero at all times

This is a multiple choice question that I cannot figure out... This is a question for a test... but the teacher lost the key and has to redo the problems and I am helping him with it... but we are unsure about this question.

I'm not sure I can treat the loop as a particle, and it seems that if the loop induced a current, the forces would cancel out/not go left or right...

Thanks

2. Apr 20, 2010

### ideasrule

Think about this: which way does the current flow in the loop as it enters a region? What force does the magnetic field exert on each side of the loop?

3. Apr 20, 2010

### brianfast

B? 4char

4. Apr 20, 2010

No, not B.