Physics 106, S
Reading: Chapters 20 Sec. 8-10
Did you complete the reading assignment?
Did you complete the entire quiz or spend at least 15
minutes working on this quiz and the attached links?
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:
(Yes, it's on YouTube and not Wiki - the cousin to the source of
Why does it take so long for the waterwheel to start turning?
There needs to be a large enough mass of water to overcome the static friction of the waterwheel bearing.
Would a heavier wheel take more or less time to get started?
Does the water wheel seem to provide much resistance to the flow of water
after it has been spinning for a while?
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)
According to Faraday's law, when the amount of current is changing through a wire loop a magnetic field will be formed which induces (creates) a current going in the other direction. This is how an inductor resists flow of current.
Would an inductor with more loops in its coil have more or less resistance to
Will an inductor provide much resistance to the flow of water
after current has been flowing for a while?
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Was there anything that you didn't understand in the reading assignment?
What was confusing to you?