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serverxeon
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Homework Statement
You have an iron ring, hung near a solenoid which has an iron core inserted within.
[PLAIN]http://img843.imageshack.us/img843/1623/imgsole.jpg
Below are the questions and answers my book provided. I highly suspect the reasoning and i seek PF members to evaluate how true it is.
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a) What happens when the switch is closed?
Ans: There will be a change in the magnetic flux going through the ring, and according to lens law, a current will be induced such that the resulting magnetic field opposes the change.
Hence, the ring will swing away momentarily.
b) What happens when the potential divider is brought to X quickly?
Ans: There will be a change in the magnetic flux going through the ring, hence, the ring will swing towards the solenoid momentarily
c) What happens when the potential divider remains at X?
Ans: The ring will remain at rest (ie. at equilibrium position)
d) What happens if the potential divider is brought between X and Y at 2Hz?
Ans: The ring will oscillate back and forth at 2Hz
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My intuition tells me that the ring should be attracted to the solenoid, just like a normal metal to a bar magnet, regardless of change in flux, or polarity.
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