Chapter 9: Magnetism
MULTIPLE CHOICE
1. The ____ is created by rubbing a piece of soft iron with a piece of magnetite.
a.
artificial magnet
c.
permanent magnet
b.
electromagnet
d.
temporary magnet
2. Magnets that retain only a small portion of their magnetic properties are called ____.
a.
artificial magnets
c.
permanent magnets
b.
electromagnets
d.
temporary magnets
3. The characteristic that determines whether a substance is ferromagnetic or not is called ____.
a.
retentivity
c.
residuality
b.
permeability
d.
polarity
4. The strength of the magnetic field is ____ the number of turns in the coil and the amount of current
flowing through it.
a.
double
c.
directly proportional to
b.
half
d.
inversely proportional to
5. ____ is the effect a magnet has on an object without physical contact.
a.
Magnetic induction
c.
Magnetic shield
b.
Electromagnetic induction
d.
Magnetic field
6. Low-reluctance materials are called ____.
a.
magnets
c.
magnetic shields
b.
electromagnets
d.
magnetic fields
7. ____ is the principle behind the generation of electricity: When a conductor passes or is passed by a
magnetic field, a current is produced (induced) in the conductor.
a.
Magnetic induction
c.
Magnetic shield
b.
Electromagnetic induction
d.
Magnetic field
8. Faraday’s law, the basic law of electromagnetism, states: The induced voltage in a conductor is ____
the rate at which the conductor cuts the magnetic lines of force.
a.
double
c.
directly proportional to
b.
half
d.
inversely proportional to
9. An alternating current (AC) generator converts ____ energy to electrical energy by utilizing the
principle of electromagnetic induction.
a.
electromagnetic
c.
mechanical
b.
chemical
d.
heat
10. A(n) ____ is an electromechanical switch that opens and closes with an electromagnetic coil.
a.
solenoid
c.
AC generator
b.
relay
d.
DC generator
COMPLETION
1. As electrons orbit around the nucleus of the atom, they spin on their axis, like the earth as it orbits the
sun. This moving electrostatic charge produces a(n) ____________________.
2. When current flows in opposite directions through two conductors placed next to each other, the
resulting magnetic fields ____________________ each other.
3. When current flows in the same direction through two conductors placed next to each other, the
magnetic fields ____________________.
SHORT ANSWER
1. Provide evidence for the “domain theory” of magnetism.
2. List the important characteristics possessed by flux lines.
