Forces And Energy Chapter 7

Front 1

define magnet

Back 1

any material that attracts iron and materials that contain iron

Front 2

who first discovered magnets ?

Back 2

the greeks

Front 3

what are 3 proprieties that all magnets have?

Back 3

-attract iron and materials containing iron

-attract and repel other magnets

-one part of the magnet will always point north when allowed to swing freely

Front 4

what are the 2 poles of a magnet?

Back 4

the place on a magnet where the force is strongest

Front 5

what happens if you put the North pole of a magnet next to the North pole of a second magnet?

Back 5

they will repel

Front 6

what is the term for a push or pull that can cause an object to move?

Back 6

force

Front 7

what is the force of attraction or repulsion between 2 magnetic poles called?

Back 7

magnetic force

Front 8

where on a magnet is the force strongest?

Back 8

the poles

Front 9

what is the term for the tiny, negatively-charged particles in the outer region of atom?

Back 9

electrons

Front 10

what causes the magnetic field of an atom?

Back 10

the spinning of an electron

Front 11

why are most objects' magnetic proprieties too weak to be detected?

Back 11

some atoms produce a a magnetic field in which their atoms point in random directions that create a magnetic field too weak to detect

Front 12

what is a grouping of atoms that have their magnetic fields lined up called?

Back 12

magnetic domain

Front 13

how do the magnetic domains in magnetized and unmagnetized materials differ?

Back 13

in unmagnitized materials domains point outward in random directions, and cancel each other out. In a magnetized material all or most of the domains are arranged in the same direction.

Front 14

define ferromagnetic material

Back 14

a material that shows how strong magnetic effects to be

Front 15

define magnetic field

Back 15

the region of magnetic force around a magnet

Front 16

where do magnetic field lines cross?

Back 16

they never cross

Front 17

where do magnetic field lines come closet together?

Back 17

at the poles

Front 18

how do you get a combined magnetic field?

Back 18

when the magnetic field of two or more magnets overlap

Front 19

how does a compass work for finding direction?

Back 19

with a magnetized needle that can spin freely it can find direction

Front 20

what is magnetic declination, and what determines it?

Back 20

the angle difference between the location of Earth's magnetic poles.

Front 21

what is electromagnetism?

Back 21

the relationship between electricity and magnetism, where an electric current will produce an electric field

Front 22

what are the benefits of a magnetic field produced by a current?

Back 22

1.) you can increase the amount of current in the wire to increase the magnet field

2.) you can make a loop or coil in the wire. When a loop is made the magnet field line bunches together, and each loop strengthens the magnetic field

Front 23

describe the 2 ways you can change the strength of a magnetic field.

Back 23

1.) you can increase the amount of current in the wire to increase the magnet field

2.) you can make a loop or coil in the wire. When a loop is made the magnet field line bunches together, and each loop strengthens the magnetic field

Front 24

what is similar and different between a solenoid or electromagnet?

Back 24

a solenoid uses electric current and coiled wires to produce magnetic fields. An electromagnet is a strong magnet that can be turned on and off. You can change the north and south poles of a solenoid by changing the direction of the current.

Front 25

how do you change the north and south poles of a solenoid or electromagnet?

Back 25

You can change the north and south poles of a solenoid by changing the direction of the current.

Front 26

what are the 4 ways you can increase the strength of an electromagnet?

Back 26

1.) Increase the current of the solenoid

2.) add more loops to the wire

3.) you can wind the coils of the solenoid closer together

4.) you can also use a material that is more magnetic than iron for the core

Front 27

where are electromagnets found?

Back 27

in electric motors, earphones, and junkyards

Front 28

define mechanical energy

Back 28

the energy an object has due to its movement or position

Front 29

what is the term for energy associated with currents?

Back 29

electrical energy

Front 30

what happens when a wire with a current is placed in a magnetic field?

Back 30

electrical energy is transformed into mechanical energy

Front 31

what is a galvanometer?

Back 31

a device that measures small currents

Front 32

how does a galvanometer work?

Back 32

an electromagnet is suspended between the opposite poles of 2 magnets. When current is in the electromagnet it produces a magnetic field that interacts with the permanent magnets causing the coil and pointer to rotate. The amount of rotation depends on the amount of current in the wire.

Front 33

what is an electric motor?

Back 33

a device that uses an electric current to turn an axle, it transforms electrical energy into mechanical energy.

Front 34

how does an electric motor work?

Back 34

a loop of wire (amateur) is held between two permanent magnets. The current is in opposite directions on each side of the amateur causing one side moves down. Two semicircular pieces of metal (commutators) rotate with the amateur. The direction of current reverses with each half turn so the amateur spins continually while the current is on.

Front 35

what direction does current flow?

Back 35

positive to negative

Front 36

define electromagnetic induction

Back 36

the generation of electric current from the motion of a conductor through a magnetic field

Front 37

what is the difference between direct current (DC) and and alternating current (AC)?

Back 37

DC is a current with charges that flow in one direction. AC is constantly reversing current, and the voltage can be easily raised or lowered

Front 38

how can you cause current to change direction?

Back 38

moving coils in a magnetic field or by moving the magnet up and down repeatedly

Front 39

how do generators compare to an electric motor?

Back 39

they are basically opposites the motor transforms electrical energy into mechanical energy the generator transforms mechanical energy to electrical energy.

Front 40

what is a transformer?

Back 40

a device that increases or decreases voltage

Front 41

describe the 2 types of transformers

Back 41

- A step-up transformer increases voltage by increasing the number of loops of wire from a primary to secondary coil. This is done to transmit high voltages long distances.

-A step-down transformer decreases voltage by decreasing the number of loops of wire from a primary to secondary coil. This is done so the voltage is ready to use in your home, because homes use lower voltage.