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8J Magnetism @ AJHS

magnets and electromagnets

QuestionAnswer
attract Two things pulling towards each other.
cobalt A metal that is a magnetic material.
iron A metal that is a magnetic material.
magnet Something that can attract magnetic materials.
magnetic materials Materials that are attracted to a magnet; iron cobalt nickel and steel are all magnetic materials.
magnetism A non-contact force.
nickel A metal that is a magnetic material.
north pole One end of a magnet. This ends points north if the magnet can move.
repel Push away.
south pole One end of a magnet.
steel A mixture made mainly from iron; it is a magnetic material.
bar magnet A straight magnet, shaped like a small bar.
compass A magnetised piece of metal that can swing around – it points north.
north-seeking pole The end of a magnet that points north if the magnet can move freely. Often just called the north pole.
south-seeking pole The end of a magnet that points south if the magnet can move freely. Often just called the south pole.
iron filings Tiny pieces of iron that are sometimes used to find the shape of a magnetic field.
magnetic field The space around a magnet where it can affect magnetic materials or other magnets.
north magnetic pole The place on the Earth where compasses point (it is not in the same place as the North Pole marked on maps).
plotting compass A small compass used for finding the direction of a magnetic field.
armature The iron part of a relay that moves when electricity is flowing in the solenoid (or electromagnet).
electromagnet A coil of wire with electricity flowing in it. An electromagnet has a magnetic field like a bar magnet.
make and break The switch in an electric bell that opens and closes. It is operated by a switch; electromagnet that breaks the circuit whenever it is switched on.
permanent magnet A magnet that keeps its magnetism – it does not depend on electricity.
reed switch A switch made from two thin pieces of metal, which closes when it is in a magnetic field.
relay A switch that is switched on and off by electricity.
solenoid A coil of wire.
core A solid bar inside an electromagnet – usually made of iron.
properties and interactions of magnets magnetism
The collection or flow of electrons in the form of an electric charge electricity
generating electricity with motion mechanically
surrounds an electric charge and exerts a push or pull on other electric charges electric field
charge that collects on the surface of an object static electricity
charge that flows through a conductor current
composed of chemical substances which can generate electrical current battery
electric current running through a wire coiled around a metal core produces this electromagnet
the way most of our electricity is produced magnetism
a machine that converts motion into electricity using magnets generator
what opposite magnetic poles do attract
To strengthen an electromagnet you should (decrease / increase) the number of loops of wire around the nail. increase
In a (parallel / series) circuit electricity can only travel ONE path. Series
The flow electrons is known as _____ electricity
Conductors have _____ resistance. Low
Adding bulbs on a series circuit will cause all of the lights (to get dimmer / to stay the same brightness) to get dimmer
If a material is used to close a circuit and the light does not light it is probably because the material used to close the circuit is a(n) ______ (conductor / insulator) insulator
If you want to produce a large, continuous amount of electricity you need a _____. Generator
If light bulbs are connected on a series circuit removing one bulbs will cause ______ all the other bulbs on the circuit to go out
An electric motor changes _____ energy into ______ energy. electric energy into mechanical energy.
Wood would be classified as a _______ (conductor / insulator) insulator
A turbine is connected to a generator to produce electricity. The turbine can be turned using ______, ______, or _______. wind, flowing water, steam
A discharge of static electricity in nature is known as ________ lightning
In a parallel circuit light bulbs can be connected in (a straight line / loops made of wires). loops made of wires
Insulators have _______ resistance. High
In a (parallel / series) circuit electricity can travel MORE THAN ONE path. Parallel
Adding bulbs on a parallel circuit will cause all of the lights (to get dimmer / to stay the same brightness) to the same brightness
Plastic would be classified as a _______ (conductor / insulator) insulator
Copper would be classified as a _______ (conductor / insulator) conductor
Electricity running through wires produces a ________. magnetic field around the wire.
In a series circuit light bulbs can be connected in (a straight line / loops made of wires). a straight line
Fabric would be classified as a _______ (conductor / insulator) insulator
Objects become electrically charged when they gain or lose _______ electrons
If you plug a small 1.5V light into a 120V outlet the light will ________. overheat from too much current
Magnetic fields are caused by moving ________. Electrons
ALL of the lights connected on a series circuit will (brighter / dimmer) than lights connected on a parallel circuit. Dimmer
An electromagnet needs to have ________. wire wrapped around an iron core and a battery or other electrical energy source
A turbine is connected to a generator to produce electricity. The turbine can be turned using steam. The steam can be created by burning ___________. fossil fuels
A generator changes _____ energy into ______ energy. mechanical energy into electrical energy.
Electrons usually flow from _____ to ______ negative to positive.
A stone or piece of metal that can attract certain things. Magnet
Pull toward each other. Attract
The force or energy that magnets possess.
magnetism A rock found in the Earth.
To push away. Repel
The ends of a magnet. Poles
An object made with a magnet that can help you find your way. Compass
The area around a magnet in which the force of the magnet acts. magnetic field
A south pole and a south pole will... repel
A south pole and a north pole will... attract
an object that has the property of attracting certain materials, mainly iron and steel magnet
A magnet's property of attracting certain materials, mainly iron and steel magnetism
One of the ends of a magnet where the magnetic force is strongest; it points to the north when the magnet moves freely. north pole
One of the ends of a magnet where the magnetic force is strongest: it points to the south when the magnet is allowed to move freely south pole
The lines that form a pattern showing the size and shape of a magnetic force field. lines of force
the space around a magnet within which the force of the magnet can act magnetic field
A naturally magnetic mineral found at or near Earth's surface. lodestone
A device containing a magnetized needle that moves freely and is used to show direction. Compass
a push or pull force
an object that sticks to iron magnet
a specific kind of force magnetism
when magnets pull together attract
when magnets pull apart repel
a piece of iron that behaves like a magnet when it is touching a permanent magnet temporary magnet
the influence of a permanent magnet's magnetic field on a piece of iron, which makes the magnet act like a magnet induced magnet
What is the affect of distance between two magnets greater the distance the weaker the force of attraction
can attract or repel each other two magnets
what detects a magnetic field? compasses, iron fillings, and iron, cobalt or nickel objects
Describe what happens when you touch a piece of iron to a permanent magnet magnetism is induced in the piece of iron, and it becomes a temporary magnet. Magnetism can be induced only in iron or steel, cobalt and nickeland a few other metals.
Explain how you stop force of magnetism Thick objects and sheets of steel stop magnetism
Explain how Magnetic force decreases the magnetic force of attraction between two magnets decreases with distance
Explain how you detect a magnetic field compasses, iron fillings, and iron objects
stop the force of magnetism thick objects and sheets of steel
What metal is attracted to magnets? Iron (also cobalt and nickel) NOT "METAL"- MOST METALS ARE NOT MAGNETIC
What are the two poles of a permanent magnet? positive (+) and negative (-)
What are the two poles of an electromagnet? positive (+) and negative (-)
What happens when two like magnetic poles are brought together? the magnets will repel
What happens when two opposite magnetic poles are brought together? the magnets will attract
What else will effect a magnet besides iron,( cobalt, and nickel)? electricity
What important difference is there between permanent magnets and electromagnets? electromagnets can be turned on and off and permanent magnets cannot
How is an electromagnet created? by passing electricity through a coil of wire
How is electricity generated? by passing a magnet through a coil of wire
What force powers an electric motor? magnetic repulsion
What force powers an engine? controlled explosion
What causes a motor to spin? the poles of the stationary magnets repel the poles of the moving magnet (armature)
What are the four principal ways of generating electricity? wind, moving water, burning fossil fuels, and nuclear
What will happen if the positive pole of one magnet is brought near the positive pole of another magnet? the magnets will repel
What will happen if the negative pole of one magnet is brought near the positive pole of another magnet? the magnets will attract
What will happen if the negative pole of one magnet is brought near the negative pole of another magnet? the magnets will repel
A magnet exerts a force on any piece of material which is . . . magnetic Because Means affected by a magnet !
Magnetic materials include . . . iron, steel, nickel and
The region of space around a magnetic which can influence magnetic materials is called a . . . magnetic field
The magnetic field of a magnet can be made visible by using . . . iron filings or plotting compasses
The end of a bar magnet which turns to point North is called the . . . North-seeking pole
A bar magnet which is suspended by a thread will eventually . . . come to rest pointing North-South Because The magnet aligns itself with the Earth's magnetic field
The Earth has a magnetic field around it which resembles that of a . . . bar magnet Because It looks similar but this does not mean there is a bar magnet at the centre of the Earth
When a coil of wire has an electric current flowing in it, the coil acts like a . . . bar magnet
The magnetic field in an electromagnet can be made stronger by . . . increasing the current or by using more turns of wire
A strong electromagnet needs to have a core made of . . . soft iron
If a steel rod is placed inside an electromagnet it will . . . become permanently magnetised but only if the coil carries a direct current
A magnet can be de-magnetised by placing it inside a coil carrying . . . alternating current Because This scrambles the atomic magnets and reduces the magnetic field in the magnet to zero
Reversing the current direction in an electromagnet . . . reverses the poles Because This is what AC does 50 times a second
Electromagnets are used in devices called . . . circuit breakers ( and relays ) Because When a large current flows, the electromagnet attracts an iron bar which opens a switch
When a wire carrying an electric current is placed in a magnetic field it may experience a . . . force
The force on a coil of wire in a magnetic field is the principle of the . . . electric motor which spins continuously in one direction
In a simple dc motor, the device which allows it to spin continuously in one direction is called a . . . split ring commutator Because It reverses the direction of current every half turn
If a magnet is moved into a coil of wire which is part of a complete circuit, a current is . . . induced Actually a voltage is induced first and then a current flows in the circuit
If a magnet is moved in and out of a coil, the direction of the induced current will . . . reverse Because that is, change from one direction to the opposite direction
The production of electricity by means of a coil of wire moving in a magnetic field is called . . . electromagnetic induction
A device which changes the voltage of an AC supply is called a . . . transformer
Transformers are used at power stations to . . . increase the voltage of the electricity supply to reduce energy losses
Power lines carry electricity at high voltage because . . . this reduces energy losses
Electricity supplied by the National Grid is at 400 000 volts. This is too high to use in the home so the voltage must be . . . reduced by a transformer, called a 'step-down' transformer
A generator consists of . . . a coil of wire rotating in a magnetic field. It produces alternating current
A transformer can only work with AC because . . . it needs a changing magnetic field to induce a voltage in the seconday coil
If a wire or coil moves through a magnetic field we say it is . . . cutting the lines of force
When a wire cuts through a magnetic field . . . a voltage is induced between its ends Because A current will flow if we connect the wire to a complete circuit
If a coil rotating in a magnetic field is spun faster, the voltage induced will . . . increase
To increase the voltage induced in a coil rotating in a magnetic field we could . . . increase its area or the number of turns Or make the field stronger
An AC generator consists of . . . a coil rotating in a magnetic field. Power stations have several of these going at the same time
The current is taken from a generator by means of . . . slip rings and brushes. This prevents sparks ( or tangled wires ).
The brushes in a generator or motor are usually made from . . . graphite ( carbon ) Because It's a good conductor and it's slippery
A transformer works because . . . an alternating current in the primary coil induces another alternating current in the secondary coil
A transformer needs a soft iron core because . . . it transfers the magnetic field from the primary to the seconday coil. Only AC can produce a rapidly changing magnetic field
When an alternating voltage is applied across the primary coil of a transformer . . . an alternating voltage is produced (induced) across the secondary coil
common ferromagnetic materials iron, nickel, and cobalt
magnetosphere the region of Earth's magnetic field shaped by the solar wind
solar wind streams of electrically charged particles flowing at high speeds from the sun
magnetic field the region around a magnet where the magnetic force is exerted
an aurora the Northern Lights
magnetism the force of attraction or repulsion of magnetic materials
temporary magnet easily loses its magnetism
magnetic domain a cluster of billions of atoms that all have magnetic fields lined up in the same way
unlike magnetic poles attract each other
like magnetic poles repel each other
magnetic field lines never cross; they form complete loops from pole to pole; they spread out as they get farther from the magnet
the poles where the magnetic force is the strongest
magnetic properties of a material depend on its atomic structure
every magnet, regardless of its shape, has two magnetic poles
a spinning electron produces a magnetic field
solenoid a coil of wire with a current
electromagnet a solenoid with a ferromagnetic core
electromagnetism the relationship between electricity and magnetism
an electric current produces a magnetic field
the two ends of a solenoid act like poles
the magnetic pole in the Northern Hemisphere is in Northern Canada
one part of a freely swinging magnet always points to Earth's magnetic pole in the Northern Hemisphere
most materials are not magnetic because their magnetic domains are arranged randomly
as Earth's magnetic pole moves, the magnetic declination in a given location will change
you can destroy a magnet's magnetism by heating it or by dropping it or by striking it hard
since Earth produces a strong magnetic field, Earth can make magnets
a magnet made from a steel paperclip is most likely a temporary magnet
a compass behaves as it does because of Earth's magnetic field
Earth's magnetic field can make a magnet out of an iron bar by causing the magnetic domains to line up in the same direction
if you break a magnet in half each half will be a new magnet, with both a north and south pole
when molten material hardens into the rock on the ocean floor, the domains of the iron it contains line up in the direction of Earth's magnetic field
uses of an electromagnet include lifting heavy metal objects with a crane at a junkyard; recoding a song onto an audiotape; and recording a television show onto a videotape
you can increase the strength of an electromagnet's field by using a stronger ferromagnetic material for the core; increasing the current in the solenoid; increasing the number of loops in the solenoid; and winding the coils more tightly
Magnetism is a physical property that we cannot sense
a proton in motion is capable of creating a magnetic field
Alnico is a combination of aluminum, nickel & cobalt; is 1 of the more useful magnets produced from ferromagnetic material; can be permanently magnetized
a battery is a source of electromotive force
circuit containing a solid-state diode electrons will be permitted to flow in one direction but not the other
Magnetism is one of the fundamental forces.
Electromagnets is a temporary magnet produced by a moving electric current
Differences beween electron flow & conventional current flow electron flow is actually from negative to positive poles while conventional electric current is described as going from positive to negative poles.
thumb pointing movement of conductor
index finger magnetic lines of force field
middle/other finger current or electron flow
3 ways to induce electromagnetic current flow in a conductor 1- move the conductor through a unchanging-strength magnetic field; 2- move magnetic lines of force through a stationary conduction with an unchanging-strength magnetic fields; 3- vary the magnetic flux strength from a stationary magnet through
4 factors controlling strength of electromagnetically induced current 1- the strength of the magnetic field; 2- the speed of the motion b/t lines of force & conductor; 3- the angle b/t the magnetic lines of force & the conductor; 4- the number of turns in the conduction coil
differences of a generator & motor generator converts mechanical energy to electrical energy & a motor converts electrical energy to mechanical energy.
Diode creates an electrical "one way street" by permitting electrons to flow easily in 1 direction while offering a high resistance to movement in the other direction
Created by: johncl