Reflection and Refraction > Electromagnets Flashcards
(121 cards)
1
Q
Based from the Magnetism Lab Sheet, what do you notice about the interaction of the bar magnets you were given?
A
the iron filings are attracted to the south pole of the magnet
2
Q
Based from the Magnetism Lab Sheet, why did the iron filings behave that way?
A
the iron filings are more attracted to the southern pole of the magnet
3
Q
what a material contains when it has the ability to exert forces on magnets or other magnetic materials
A
magnetic force
4
Q
a material that keeps its magnetic properties even when it is not close to other magnets
A
permanent magnet
5
Q
magnets have ? poles
A
two opposite
6
Q
poles of a magnet
A
north
south
7
Q
the ends of a magnet
A
poles
8
Q
Magnetic forces depend on the ——— of the poles
A
alignment
9
Q
magnets exert —— on each other
A
forces
10
Q
virtually transparent to magnetic forces
A
insulating materials (wood, plastic, etc.)
11
Q
conducting materials (aluminum, etc.) also allow magnetic forces to pass through, but may —— the forces
A
change
12
Q
the strength of the force between magnets depends on the ——– between them
A
distance
13
Q
magnetic force ——— with distance much faster than does either gravity or the electric force
A
decreases
14
Q
two basic types of magnets
A
natural
artificial
15
Q
all magnets create a ——– —– in the space around them, and the ——– —– creates forces on other magnets
A
magnetic field
16
Q
the field of influence that a magnet creates around it
A
magnetic field
17
Q
a black metallic ore that has strong magnetic property
A
lodestone
18
Q
the number of field lines in a certain area indicates the relative ——— of the magnetic field in that area
A
strength
19
Q
the arrows on the field lines indicate the ——— of the force
A
direction
20
Q
the —— the lines are together; the ——- the field
A
closer; stronger
21
Q
magnetic field lines ALWAYS point —- from a magnet’s north pole and —— its south pole
A
away; toward
22
Q
sources of nearly all magnetic effects in matter
A
electrons in atoms
23
Q
two ways in which electrons create magnetism
A
- electrons around the nucleus and their motion makes the entire atom a small magnet
- electrons themselves act as though they were magnets
24
Q
ALL atoms have electrons, but there is a great ———– in the magnetic properties of materials
A
variability
25
electrons in some atoms ----- to cancel out one another's magnetic influence
align
26
a property of a material when its electrons are oriented so their individual magnetic fields CANCEL each other out [slightly repelled]
diamagnetic
27
a property of a material when its individual atoms are magnetic but the atoms themselves are randomly arranged so the OVERALL magnetism of a sample is zero
paramagnetic
28
a material that has very strong magnetic properties
ferromagnetic
29
examples of ferromagnetic materials
```
iron
nickel
cobalt
gadolinium
dysprosium
```
30
a group of atoms with similar alignment or orientation towards a magnet
magnetic domain
31
examples of diamagnetic materials
```
antimony
zinc
copper
gold
silver
table salt
mercury
alcohol
water
hydrogen
air
argon
```
32
examples of paramagnetic materials
```
aluminum
chromium
alkali metals
platinum
oxygen
wood
```
33
magnetic domains in a ferromagnetic material will always orient themselves to attract a --------- magnet
permanent
34
if a ----- pole approaches, domains grow that have south poles facing out
north
35
if a ----- pole approaches, domains grow that have north poles facing out
south
36
materials that make good permanent magnets
hard magnets
37
a common and inexpensive material, which contains iron and carbon, used to create hard magnets
steel
38
materials that lose their magnetism quickly
soft magnets
39
By 1200, Italian explorers were using a ------- to guide ocean voyages beyond the sight of land
compass
40
when using a compass, the north-pointing end of a needle points toward a spot near the Earth's geographic ----- pole
north
41
the Earth's magnetic poles are defined by the planet's magnetic -----
field
42
the ----- magnetic pole of the planet is near the north geographic pole
south
43
natural force that causes magnets to attract other particles
magnetic force or magnetism
44
it will pull some metals toward itself
magnet
45
what is the rule of magnetism?
it is a force of attraction or repulsion that acts at a distance between various substances
46
What happens to the two poles if you break a magnet in half?
the fragment with N pole will have an S pole and vice versa
| "the poles adjust"
47
the ---- of a magnet are where the magnetic force is the strongest
ends
48
magnetic field lines leave the ----- end of a magnet and enter the ----- end of a magnet
north; south
49
region where the magnetic forces act
magnetic field
50
The Earth behaves as if there was a ------ in its interior
magnet
51
a compass will always point towards the -----
North
52
magnetized piece of metal that can spin
compass
53
a compass ------ to a magnetic field from a magnet
reacts
54
discovered the deflection of a compass needle while performing a demonstration for his students
Hans Christian Oersted
55
discovered the fundamental connection between electricity and magnetism
[electricity = magnetism]
Hans Christian Oersted
56
what happens to a wire when it carries electricity?
a current-carrying wire becomes a magnet by setting up a magnetic field around it
57
what is your proof for this: "current-carrying wire becomes a magnet by setting up a magnetic field around it"?
deflection of the compass needle
58
according to Oersted's experiment, when current is present, the needle deflects ------------- to the wire
perpendicular
59
according to Oersted's experiment, when current is reversed, the needle deflects in the --------- direction
opposite
60
Hans Christian Oersted's principle
"a charge moving through a straight conductor produces a circular magnetic field around it"
61
remember!
electric current from + to the - terminal of the battery
RIGHT HAND GRIP RULE
62
what happens to the magnetic field around the wire if we flip the direction of current?
the magnetic field around the wire changes direction when the flow of current changes
63
what is your proof for this: "the magnetic field around the wire changes direction when the flow of current changes"?
the flipping of the compass needle to the other direction
64
if the current through the wire increases, the strength of the induced magnetic field --------
increases
65
a long coil of several turns of wire
solenoid
66
the magnetic field inside a solenoid is -------- than the magnetic field outside it
stronger
67
the concept of solenoid led to the creation of a simple -------------
electromagnet
68
devices that create a magnetic field through the application of electricity
electromagnet
69
if the number of coils in a wire increases, the strength of the induced magnetic field ---------
increases
70
tubular coil of wire with many turns
solenoid
71
a temporary magnet made by passing electric current through a wire coiled around an iron bar
electromagnet
72
consists of an iron core placed inside a wire coil
electromagnet
73
uses of electromagnets
```
doorbells
could send spacecraft deep into space
pick up and drop junked cars
trains (maglev, bullet, etc.)
loudspeakers (consist of permanent magnet surrounding an electromagnet)
```
74
invented electric motor, generator and transformers
Michael Faraday
75
discovered electromagnetic induction
| [magnetism = electricity]
Michael Faraday
76
Michael Faraday's conclusions
an electrical current is produced by constantly changing the magnetic field
77
converts mechanical energy to electrical energy
generator
78
current that flows in one direction
direct current (DC)
79
current that flows in a back-and-forth manner
alternating current (AC)
80
converts electrical energy to mechanical energy
motor
81
a current coming out of the plane will have its magnetic field turning:
a. counter clockwise
b. clockwise
a. counter clockwise
82
when ------------ materials are placed in a magnetic field, the atoms align so that the material has a weak magnetic force
paramagnetic
83
symbol used to denote the direction of a current into the plane
(.) and (x)
84
bending of a wave as it passes through different media
refraction
85
why is an iron core needed in an electromagnet?
an iron core is necessary to make the magnet stronger
86
how are electromagnets different to either temporary or permanent magnets?
an electromagnet can be turned on and off
87
to increase the magnetic field of an electromagnet, use a more powerful -------
battery
88
type of wire (based from the web quest)
the copper wire attracts the most number of filings
89
thickness of the wire (based from the web quest)
the thicker the wire, the more iron filings are attracted
90
AC or DC power supply (based from the web quest)
DC power supply attracts more iron filings
91
voltage (based from the web quest)
the higher the voltage, the more iron filings are attracted
92
number of winds [turns] in the wire (based from the web quest)
the more number of winds, the more iron filings are attracted
93
describe how an electric bell works
- when the current flows through the circuit, the electromagnet makes a magnetic field
- the electromagnet attracts the springy metal arm
- the arm hits the gong, which makes a sound
94
how is a magnet used inside of a simple AC generator
- a wire passing through a magnetic field causes electrons in that wire to move together in one direction
- a steam engine or some other outside source of motion moves the wire or armature through the magnetic field created by the magnets
- the loop is spinning; which means that the flow of electrons keeps changing!
95
ferromagnetic materials have ---- unpaired electrons than paramagnetic materials
more
96
if an electromagnet has a high voltage, then its magnetic capability ---------
increases
97
change in magnetic flux
electromagnetic induction
98
generates electricity by manipulating the magnetic field within an area
electromagnetic induction
99
Between two upright circles, (a) bigger (b) smaller, which will contain more magnetic flux?
(a) bigger
100
Between (a) an upright circle and (b) a horizontal circle, (a) will contain ---- magnetic flux
more
101
more perpendicular, ------ magnetic flux
higher
102
- the product of the average magnetic field times the perpendicular area that it penetrates
- quantity of convenience in the statement of Faraday's Law and in the discussion of objects like transformers and solenoids
Magnetic flux
103
- (often denoted Φ or ΦB) through a surface
| - its SI unit is the weber (Wb) (in derived units: volt-seconds)
magnetic flux
104
describe how the appearance of a pencil point changes as it moves closer the concave side of the spoon
the image slowly becomes upright and the size magnifies
105
describe how the appearance of a pencil point changes as it moves closer the convex side of the spoon
the orientation of the pencil point is still upright however the size reduces
106
describe the appearance of the coin if you were able to see it with the water in the cup (clear, plastic)
We were able to see it since we came from low N to high N. The image appears more shallow and visible.
107
why did the spoon appear to be "broken" inside that cup?
it appeared broken because of the change in density
108
what happened to the letters of the newspaper when water droplets were placed on the plastic wrap?
letters were magnified
| water droplets act as a lens
109
what happened to the letters of the newspaper when the plastic wrap is folded in half?
image's magnification appeared the same as the actual text
| image was blurry
110
the smaller the droplet, the ---- the magnification
more
111
-------- ------- in compasses are used in navigations
magnetic needles
112
As charges move (such as in an electric current), --------- can be induced
magnetism
113
historians believed that they were the first to build compasses to help them navigate the seas
Chinese
114
Greek philosopher associated with "magnets" and also the first to observe its property
Thales
115
it was given the name "------" after Magnesia, a district in the Asia Minor
magnet
116
Another tale about magnets was based on the story of a shepherd named ------
Magnes
117
attracts alloys
magnets
118
not able to retain their magnetic ability after losing contact with a magnet
paramagnetic materials
119
artificial magnets are made through ------- ---------
induced magnetism
120
types of artificial magnets
permanent
| temporary
121
magnets made of pure and soft iron
temporary magnets
