Go Back   Physics Help Forum > College/University Physics Help > Advanced Electricity and Magnetism

Advanced Electricity and Magnetism Advanced Electricity and Magnetism Physics Help Forum

LinkBack Thread Tools Display Modes
Old Oct 5th 2012, 12:33 PM   #1
Junior Member
Join Date: Sep 2012
Posts: 4
Is EMF generated in this special loop of wire

A square loop of wire is kept hanging upright and has 3 sides made of copper and the lower horizontal side made of iron. The loop has its surface normal to a uniform magnetic field B. The question is: If the loop is allowed to fall while fully immersed in this field B, will an EMF be generated in the loop? Why?

Last edited by fogo57; Oct 5th 2012 at 04:31 PM. Reason: correction in the field orientation relative to loop
fogo57 is offline   Reply With Quote
Old Oct 15th 2012, 09:15 PM   #2
Junior Member
Join Date: Oct 2012
Location: Penticton British columbia Canada
Posts: 10
My understanding is yes. It doesn't matter which is moving, either the field moves relative to the wire or vise versa a force will be realized. To add to your question. If the wire is moveing toward the field the force moves in a certain direction and when you move it away the direction of current changes as well. In a figure of 8 loop of wire the current moves clockwise on one loop of the 8 and counter clockwise in the other all the while you are moving either the loop or the wire, with or without an iron section to close the loop.


Last edited by nullflux8; Oct 15th 2012 at 09:17 PM. Reason: changed of to or
nullflux8 is offline   Reply With Quote
Old Oct 16th 2012, 05:06 AM   #3
Junior Member
Join Date: Sep 2012
Posts: 4
EMF in a special loop of wire. Discussion and CHALLENGE

Thanks for replying. First of all I wish to point out that the Magnetic field is uniform and HORIZONTAL. THe loop is not falling onto the magnet, but it is hanging upright and parallel to the magnets surface.
There are arguments for and arguments against the appearance of an EMF. I will give the "positive" argument. The two horizontal sides are made of magnetically different materials. The local B field inside the Fe side is about twice as strong than in the Cu side. A metallic bar moving in a magnetic field B will develop an EMF given by the product x*v*B, where x is the length, v is the velocity and B the field. Of course the Bs on both horizontal sides ( taken as the bars) are very different and the EMFs subtract each other, which would produce a net EMF force in the loop and a current flowing round it. I challenge the readers to point out a flaw in this argument ( of course doing the experiment would clarify everything!).
fogo57 is offline   Reply With Quote

  Physics Help Forum > College/University Physics Help > Advanced Electricity and Magnetism

emf, generated, loop, special, wire

Thread Tools
Display Modes

Similar Physics Forum Discussions
Thread Thread Starter Forum Replies Last Post
Loop the loop question antonravik Kinematics and Dynamics 8 Nov 9th 2012 09:49 PM
What is the specification of the rebar tie wire and loop wire ties? bearfrods Electricity and Magnetism 0 Feb 26th 2012 10:06 PM
current loop, determine magnitude of force acting on loop. rcmango Electricity and Magnetism 2 Jul 31st 2011 11:22 PM
Induction in a loop of wire AStaunton Electricity and Magnetism 5 Feb 11th 2011 12:13 PM
the effect of change in area of a wire loop...? pinkprincess08 Advanced Electricity and Magnetism 1 May 2nd 2009 07:52 PM

Facebook Twitter Google+ RSS Feed