# Question for my homework due sometime tonight (magnetism, inductance, and transformers)

Discussion in 'Homework Help' started by Cameron Fife, Nov 12, 2014.

1. ### Cameron Fife Thread Starter New Member

Nov 1, 2014
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Hey guys, I would love help on the following questions. A response to any of these would be great.

1.) Which magnet motion past the wire will produce the greatest voltmeter indication: perpendicular, parallel, or no motion at all?

2.) An audio speaker has its cone attached to a metal slug that slides in and out of the core of an inductor. What would happen if someone were to gently tap on the cone of one of these speakers? What would the other speaker do? In terms of electromagnetism and electromagnetic induction, explain what is happening.

3.) The ignition coil of a gasoline-powered internal combustion automobile engine is an example of a transformer, although it is not powered by alternating current. (See below.) Explain how a transformer may be operated on electricity that is not AC:

Any responses (even just hints) appreciated. I want to understand these well but I also have about 2.33 hours to finish these and I don't know much about the concepts. Thanks!

Jul 18, 2013
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What conclusion or have you found so far?
Max.

3. ### Cameron Fife Thread Starter New Member

Nov 1, 2014
18
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Well I understand the perpendicular would be best, not perfectly sure why.

Nov 1, 2014
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5. ### tshuck Well-Known Member

Oct 18, 2012
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So, when is a magnetic field created in a coil of wire? What is required to maintain the field?

6. ### Cameron Fife Thread Starter New Member

Nov 1, 2014
18
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1.) Parallel motion will because current is always perpendicular to the magnetic field.

2.)
If Speaker 1, is tapped, Speaker 2 would create noise. Electric currents create an electric field. An electric field creates current when it’s in motion. When you tap the speaker, you are moving the magnet of speaker one, which creates a current and moves the magnet of Speaker 2. Therefore, Speaker 2 creates a noise too.

OK, I wrote answers to 1 and 2, your reactions are appreciated.

7. ### Cameron Fife Thread Starter New Member

Nov 1, 2014
18
0
A magnetic field is created when electricity runs through the wire. Right? And in order to maintain it you have to keep a current running.

8. ### WBahn Moderator

Mar 31, 2012
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5,758
Your description of Problem #2 if very vague. You say that AN audio speaker is connected to a metal (not necessarily a magnet and not necessarily magnetic) slug in an inductor. But then you go talking about another speaker without describing how the speakers are connected.

9. ### WBahn Moderator

Mar 31, 2012
20,237
5,758
So how can you say you understand it if you don't know why?

Is this just a straight piece of wire?

How can a magnetic field be used to produce a voltage in a wire? Hint: Think of Physics II and Maxwell's Equations.