chapter 20 study guide

Question 1

be able to identify arrangements of atoms in a nonmagnetic material

Answer 1

arrows pointing all different directions

Question 2

name some elements that are ferromagnetic

Answer 2

iron, nickel, cobolt

Question 2

be able to identify arrangements of atoms in a material that is attracted by magnet, but is not a magnet

Answer 2

arrows all pointing same way

Question 3

as a nail approaches the south pole of a magnet, what happens to its magnetic domains?

Answer 3

the north poles of the domains point toward the magnet

Question 4

what happens to an object that is made of magnetic materials but is not a magnet when it comes in contact with one?

Answer 4

its magnetic domains fall into alignment and it begins to attract other objects made of magnetic material

Question 5

how can you make an item that is made of magnetic material become a permanent magnet instead of a temporary magnet?

Answer 5

put in strong magnetic field

Question 6

as the electric current through a wire increases, what happens to the magnetic field around the wire?

Answer 6

it becomes stronger

Question 7

what do a permanent and electromagnet have in common?

Answer 7

north and south poles

Question 8

for an electromagnet to attract and then repel the permanent magnet in an audio speaker, what must happen?

Answer 8

must reverse directions

Question 9

what is the purpose of a commutator in an electric motor?

Answer 9

reverses direction of current in electromagnet to keep motor spinning

Question 10

what makes the electric motor spin?

Answer 10

permanent magnet and electromagnet continuously attract and repel each other

Question 11

what conditions are necessary for a magnet inside a wire loop to produce an electric current

Answer 11

must be in motion

Question 12

how can a wire and a magnet create an electric current?

Answer 12

magnet moves inside coil of wire and coil of wire moves through magnetic field

Question 13

electromagnet and permanent magnet both have _______

Answer 13

north and south poles

Question 14

when a power plant sends out high voltage electricity for long distance transmission, what is needed to make the electricity usable in houses?

Answer 14

step-down transformer

Question 15

which part of electrical transmission increases voltage for transmission?

Answer 15

step-up transformer

Question 16

south pole of a magnet will attract the ______ of another magnet

Answer 16

north pole

Question 17

what do you get when you break an iron magnet into two pieces?

Answer 17

two north and south poles

Question 18

the location of the strongest magnetic field is the magnetic _______

Answer 18

poles

Question 19

what is the region around a magnet where the magnetic forces act?

Answer 19

magnetic field

Question 20

an _____ can only operate when the current is on

Answer 20

electromagnet

Question 21

changing the current changes the _____ and ______ of an electromagnet

Answer 21

strength and direction

Question 22

name the device that increases or decreases voltage in a power line

Answer 22

transformer

Question 23

what type of current does not reverse direction?

Answer 23

direct

Question 24

what type of current reverses in a regular pattern?

Answer 24

alternating

Question 25

a boy is watching an old television show about people stranded on an island. one of the characters wanted to make an electric generator out of a bicycle. what does he need to find?

Answer 25

two magnets and a coil of wire

Question 26

what type of energy does a power plant need to produce electricity?

Answer 26

mechanical

Question 27

what kind of energy are you providing as you turn the crank on a simple electric generator?

Answer 27

mechanical

Question 28

why does a paperclip become a magnet when touching a magnet?

Answer 28

all of the paperclips’ magnetic domains line up according to polarity of original magnet