# Quick question on Faraday's law.

So i'm studying for my physics final, and I ran across a problem that is giving me a bit of trouble.

http://cyclotron.tamu.edu/dhy/sample_final_exam.pdf [Broken]

the question is 3b.

I'm thinking that the wire loop will have no induced current in it since there isn't a change in flux when you consider a loop rather than a bar, but it doesn't seem right that a 13 point problem would have such a simple answer.

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OlderDan
Homework Helper
cair0 said:
So i'm studying for my physics final, and I ran across a problem that is giving me a bit of trouble.

http://cyclotron.tamu.edu/dhy/sample_final_exam.pdf [Broken]

the question is 3b.

I'm thinking that the wire loop will have no induced current in it since there isn't a change in flux when you consider a loop rather than a bar, but it doesn't seem right that a 13 point problem would have such a simple answer.
I think you've got it. If you look at it from the point of view of charges moving with velocity v through a magntetic field, charges in both vertical parts of the loop will be forced in the same direction. There will be shift of charge until the electric force offsets the magnetic force, but no net current flow. Charges in the top and bottom of the loop just get pushed to the side of the wire.

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quasar987
Homework Helper
Gold Member
Dan,

what happens in the case of Figure (a)? Is there a separation of charges, positive ones accumulating at the top of the stick, negative ones at the bottom?

OlderDan