Current, Electricty and Electrons

[USCTrojan11]

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Hi this is question based on an MCAT question I saw in an old Kaplan.

So a wire is coiled around a steel rod with a complete circuit (something is put on the ends to give it a complete circuit). No current flows at first. There is a magnetic field around the coil. When a hammer hits the steel rod, current flows. So based on this theres a few questions.

1. Are there e-'s inside the wire before the steel rod oscillates in the magnetic field (ie before it got hit)?

2. What is the sequence of changes of energy in this procedure? (I think its kinetic -> electrical -> heat)

3. What changes are induced in the wire when the rod oscillates?

4. Are electrons inside the wire moving even when no current is flowing?

 

[Isoprop]

1. yes, there are electrons in the wire.
2. kinetic from the hammer causes the steel to move. that causes a change in the electrical potential energy. that causes the electrons to move. the electrons come back to rest because it releases heat from the resistance of the wire.
3. there is a change in the magnetic flux. changes in the flux causes a change in electrical potential. this is what causes electrons to move and produces the current.
4. yes electrons are always moving. it's just that there is no net movement when the current is zero.


and with that i think i'll take a break from answering these forums for a while.

 

[USCTrojan11]

You are the man. I would like to send you a gift certificate. Seriously, shoot me a PM with your email and I'll send you one. Thanks

 

[Isoprop]

Haha, no problem. And if you're serious about the gift certificate, I'd be happy if you would donate to SDN instead.

I've received so much help from these forums that I want to do as much as possible to contribute back.