Here are some things to do to finish this section.
What question did you think of that could be studied, or
observation could you make that is interesting or unexpected?
Send it to the Question board!
Discuss these questions with the people in your group. Please
send us a discussion of the first
question, and an answer to the others. Don't forget to tell us the group name.
The power company connects the power plant to the city
with high voltage power lines -- 100,000 V or more. Then in the city there are
a series of transformers that lower the voltage to "household" voltage
(110 V to 120 V).
This must be a very high voltage
transmission line, because the
wires are being held far away from
the tower
This is the last step in turning the
high voltage into voltage that you can
use.
Why do they bother with the high voltage lines? What
problems would appear if they tried to use household voltage for the whole network?
For example, suppose the power company is
trying to supply a city of 100,000 homes, each of which is running a 10,000 W
air conditioner.
What will happened when the switch is closed?
(The circuit is using two batteries in series, to make the equivalent of a 3V battery).
A. The buzzer will sound. The light emitting diode may glow a little.
B. The buzzer will sound. The light emitting diode won't do anything.
C. The light emitting diode will glow. The other two circuit elements won't do anything
D. All three elements will buzz or make light.
Now build the circuit, and explain the results.
Four students have proposed ways to wire a two-room house. Each room contains
one light and a switch to turn it off and on. The power company is represented as
a big battery. The red lines are the wires that the
students have added to the diagram. Which diagram is correct?
If you wire a several dozen flashlight bulbs in series and then connect
them to a battery, what will happen?
A. One of the light bulbs will burn out
B. The bulbs closest to the battery will light, but not the others
C. The lights will be on but battery will not last very long
D. None of the lights will be on.
If you wire several dozen flashlight bulbs in parallel and then connect them to a battery, what will happen?
A. One of the light bulbs will burn out
B. The bulbs closest to the battery will light, but not the others
C. The lights will be on but battery will not last very long
D. None of the lights will be on.
If there is something that you don't understand about electrical
circuits, Ask us!
This is the end of this section. (Check this
box ) The next section is about the
magnetic field.
