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Name:______________________________No:_____
Electromagnetic Induction Simulations
Directions: Open your web browser to:
http://micro.magnet.fsu.edu/electromag/java/index.html and scroll down to the respective
menu item. You will need to have Java installed for these sims—if it’s not installed on your
machine you will need to update your browser or work in the library—be patient while the
simulations load. If you have AOL at home, DO NOT use the AOL browser; instead use
Internet Explorer.
Answer the questions below & make sketches as appropriate (a picture is worth a thousand
words!); if necessary consult your textbook for extra help. Either link through the menu items or type in the addresses
directly below.
Magnetic Field Lines: http://micro.magnet.fsu.edu/electromag/java/magneticlines/
1. Field lines leave from the (North / South) Pole and enter the (North / South) Pole [circle correct answer]. Where are
field lines strongest?
Attraction and Repulsion by Magnet Poles: http://micro.magnet.fsu.edu/electromag/java/magneticlines2/
2. Like poles will _________________________ and opposite poles will _________________________.
Magnetic Fields and Compass Orientation: http://micro.magnet.fsu.edu/electromag/java/compass/
3. What happens to the orientation of the compass needle when the coil is energized by the battery when you close the
switch? What happens when the switch is opened? Why does the needle change its orientation and what is happening
inside the coil? Include sketches in your explanation.
Faraday’s Electromagnetic Induction Experiment: http://micro.magnet.fsu.edu/electromag/java/faraday/
4. Make a sketch of Faraday’s experiment below. Are the two coils connected? What happens when the switch is
closed? When the switch is opened? The compass needle deflects if there is: (a) a current flowing in the coils (b) a
change in the current flowing (circle correct one).
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Another Faraday Experiment: http://micro.magnet.fsu.edu/electromag/java/faraday2/
5. Make a sketch of Faraday’s second experiment below. What happens when the magnet is moved perpendicular to the
coil? How about when the magnet is stationary?
Lenz’s Law: http://micro.magnet.fsu.edu/electromag/java/lenzlaw/
6. What is Lenz’s Law?
As you move the magnet into the coil, in what direction is the current induced from a top view? (Clockwise / Counterclockwise).
As you move the magnet out of the coil, in what direction is the current induced from a top view? (Clockwise / Counterclockwise).
How A Metal Detector Works: http://micro.magnet.fsu.edu/electromag/java/detector/
7. Explain what are the main components of a metal detector and how a basic system would work below. Include
sketches in your explanation.
AC Generator Action: http://micro.magnet.fsu.edu/electromag/java/generator/ac.html
8. Make a sketch of an AC Generator below. Another name for AC generators:___________________________
Try changing the frequency of the coil’s rotation—how does this effect the frequency of the voltage produced?
DC Generator Action: http://micro.magnet.fsu.edu/electromag/java/generator/dc.html
9. What differences are there between an AC vs. DC generator?
How a Hard Drive Works: http://micro.magnet.fsu.edu/electromag/java/harddrive/
10. In your own words, summarize the major components of a computer hard drive and how it relies on electromagnetic
induction to operate.
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How A Speaker Works: http://micro.magnet.fsu.edu/electromag/java/speaker/
11. Make a sketch of a speaker. In your own words explain how a speaker transforms electrical energy into sound energy.
12. How a doorbell works: http://home.howstuffworks.com/doorbell2.htm
or http://home.howstuffworks.com/doorbell3.htm
Sketch below the basic operation & explain in your own words how a bell goes on/off repeatedly!
13. How a circuit breaker works: http://electronics.howstuffworks.com/circuit-breaker3.htm
Sketch below the basic operation & explain in your own words how a breaker breaks!
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How A Transformer Works: http://micro.magnet.fsu.edu/electromag/java/transformer/
14. Make a sketch of a transformer below. Are the primary and secondary coils wired together? (Yes / No).
Click on the sliders to adjust the input voltage, and the number of windings on the primary and secondary coils.
What is the input voltage, AC or DC? _______ Why? _______________________________________________
__________________________________________________________________________________________________
Complete the chart below:
Input voltage
Output voltage
12 V
12 V
12 V
120 V
120 V
120 V
Step-up or Step Down?
Coil with most windings?
(Input or Output)
12 v
84 V
1V
840 V
24 V
210 V
Transformer Summary Questions:
1. When did you observe the input and output voltages to be equal?
2. What is the function of the iron core the windings are wound around?
3. Why is high voltage used to send electrical energy over large distance in transmission wires?
4. Describe the design of a transformer that produces an output voltage that is less than the input voltage.
5. State an application of a transformer you could find in your automobile, home or school.
6. Nature does not provide a greater or smaller voltage without a loss/gain somewhere else to conserve energy. What
other electrical quantity is changed to conserve energy?