Reading Quiz 11 Key

Reading Quiz 10 Key

Due before class Friday, Jul 13th

Physics 106, Summer 2012


Reading: Chapters 20 Sec. 8-10

Did you complete the reading assignment?

Yes
No

Did you complete the entire quiz or spend at least 15 minutes working on this quiz and the attached links?
Yes
No

KEY CONCEPTS:

1) Inductance is a resist to change of current in a circuit.

2) Inductance will resist both an increase and a decrease in current.

One way to visualize the action of an inductor is to imagine a narrow channel with water flowing through it, and a heavy waterwheel that has its paddles dipping into the channel. Imagine that the water in the channel is not flowing initially.

Now you try to start the water flowing. The paddle wheel will tend to prevent the water from flowing until it has come up to speed with the water. If you then try to stop the flow of water in the channel, the spinning water wheel will try to keep the water moving until its speed of rotation slows back down to the speed of the water. An inductor is doing the same thing with the flow of electrons in a wire -- an inductor resists a change in the flow of electrons.

Here's a video clip that will help you understand this analogy, and hopefully help you understand what an inductor does: http://www.youtube.com/watch?v=Y_YEyAEwvRk&NR=1 (Yes, it's on YouTube and not Wiki - the cousin to the source of all knowledge).

Why does it take so long for the waterwheel to start turning?

Would a heavier wheel take more or less time to get started?

More
Less

Does the water wheel seem to provide much resistance to the flow of water after it has been spinning for a while?

Yes
No

In a real inductor (not waterwheels anymore) there are several loops of wire creating a coil that creates a magnetic field when current passes through it. How does this work? (Hint, think about exercise 2 from the last reading quiz)

Would an inductor with more loops in its coil have more or less resistance to current change?

More
Less

Will an inductor provide much resistance to the flow of water after current has been flowing for a while?

Yes
No

 

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Was there anything that you didn't understand in the reading assignment?  What was confusing to you?


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