Electromagnetism Electromagnetism

Concept Mapping
14. Use the following
terms to create a
concept map:
electromagnetism,
electricity, magnetism,
electromagnetic
induction, generator,
transformer.
CRITICAL THINKING AND
PROBLEM SOLVING
15. You win a hand-powered flashlight as a
prize in your school science fair. The flashlight
has a clear plastic case so you can
look inside to see how it works. When
you press the handle, a gray ring spins
between two coils of wire. The ends of the
wire are connected to the light bulb. So
when you press the handle, the light bulb
glows. Explain how an electric current is
produced to light the bulb. (Hint: Paper
clips are attracted to the gray ring.)
16. Fire doors are doors that can slow the
spread of fire from room to room when
they are closed. In some buildings, fire
doors are held open by electromagnets.
The electromagnets are controlled by the
building’s fire alarm system. If a fire is
detected, the doors automatically shut.
Explain why electromagnets are used
instead of permanent magnets.
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INTERPRETING GRAPHICS
17. Study the solenoids and electromagnets
shown below. Rank them in order of
strongest magnetic field to weakest magnetic
field. Explain your ranking.
a
b
c
d
Reading
Check-up
Current = 2 A
Current = 2 A
Current = 4 A
Current = 4 A
Take a minute to review
your answers to the
Pre-Reading Questions
found at the bottom
of page 452. Have your answers changed? If
necessary, revise your answers based on what
you have learned since you began this chapter.
Electromagnetism 477