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SPH 3U
ELECTROMAGNETISM
Review
1. From where does the word magnet originate?
2. Draw domains in a highly magnetic bar of steel. Describe the domain theory and how it is used
to explain what is created when a bar magnet is broken in half.
3. Sketch the pattern of the magnetic field around:
a) a bar magnet
b) an electromagnet
4. Why is the “north pole” of the Earth misnamed? What is the more correct term for the north
pole of a bar magnet? How was it so named?
5. Name three elements that make good magnets. These materials are known as what type?
6. Describe the basic principle of electromagnetism.
7. What is the right-hand rule (RHR) for a straight conductor?
8. Explain the RHR for a coiled conductor. Sketch a solenoid with the current direction, the m/f
lines and the poles.
9. Why would you use a piece of soft iron in a junkyard electromagnet instead of a piece of steel?
10. What three (3) factors can be used to increase the strength of an electromagnet?
11. Sketch how an electric bell operates.
12. What is the motor principle / effect? What is the RHR for the motor principle?
13. What is another name for the electromotive force ?
14. Sketch the m/f lines that show why a current-carrying conductor in the presence of a magnetic
field will move.
15. From a diagram, identify the parts of a simple single-loop motor including the commutator, split
ring, brushes, magnetic field and current carrying conductor.
16. Show the direction of spin for an armature inside a magnetic field. Include the current flow and
the magnetic poles.
17. What is electromagnetic induction? What is required for current to be continuously produced?
18. How can current be induced in a conductor (2 ways)?
19. Outline Lenz’s Law (describes the direction of the induced current).
20. What is the RHR for a generator?
21. Compare and contrast DC motors with DC generators.
22. What is a transformer? How is it useful?
23. What are step-up and step-down transformers?
24. If a transformer has 80 primary windings and 400 secondary windings, and 5.0 A is supplied
with an electric potential of 110 V, what is the output voltage and current?
25. How did the use of a transformer influence the decision to transmit AC instead of DC?
26. Who are these people and what do they have to do with electromagnetism?
a) Michael Faraday
c) George Westinghouse
b) Thomas Edison
d) Nikolai Tesla
Textbook:
pp. 543 – 543: #1 – 7; 11, 12
pp. 584 – 585: #1 – 3; 6c, 12, 17 (potential difference = voltage)
pp. 590 – 593: #4 – 6; 10, 51, 52
\sph3U\electromag\960194085
Fill in the missing information:
S
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Motors
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
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S
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Generators
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G
S
\sph3U\electromag\960194085
X
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