Chapter 14 Review                                                             Name __________________________________ Compare and contrast the three devices that use electromagnetic induction. Complete the table by placing check marks in the correct column(s).

 Step Up Transformer Step Down Transformer Generator Uses permanent magnet Uses electromagnet Creates alternating current Uses alternating current Decreases current Increases voltage

 C. ________________

2. Label these parts of the bar magnet below: magnetic field, north magnetic pole, south magnetic pole, and magnetic domains.

 B. ________________

 A. ________________

 D. ________________

3. How do magnetic field lines indicate the direction of magnetic force, and the location and strength of the field?

Figure 2 shows the earth and its magnetic field. Use the figure to answer these questions.

4. Where is the earth’s magnetic field strongest?

5. Label the magnetic north pole in Figure 2.

6. Label the geographic north pole in Figure 2.

 Figure 2 Earth’s Magnetic Field

7. What causes the electromagnet in an electric motor to spin?

In the United States, transformers adjust the voltage for appliances that use voltages greater or smaller than 120 volts.

8. Study Figure 1. Label the step-up transformer and the step-down transformer.

A ___________________                                                      B ________________________

Figure 1 Transformers

9. For each transformer in Figure 2, draw the needle in the voltmeter to indicate the relative voltage. Label the step-up transformer and the step-down transformer.

A ___________________                                                      B ________________________

Figure 2 Transformers

10. What is the function of the electromagnet in a galvanometer?

11. Sequence The following events that occur in an electric motor are in an incorrect sequence. Write the letters of the events in the correct sequence on the lines provided.

A. Electromagnet's poles repel poles of permanent magnet.

B. Electromagnet spins.

C. Drive shaft does work.

D. Poles on electromagnet reverse.                                ____  ____  ____  ____  ____  ____  ____

E. Armature turns drive shaft.                                            1       2        3         4        5       6        7

F. Current flows through electromagnet.

G. Direction of current changes.

Answer questions 1-10 on page 481

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