Physics - Chapter 24 - Magnetism

just as a current carrying wire will deflect a magnetic compass

a magnet will deflect a current carrying wire

surrounding every moving electron is

a magnetic field and a electric field

cosmis rays penetrate your body when

all the time

if a galvanometer is calibrated to measure current its called

ammeter

surrounding every stationary electron is

an electric field

a current carrying coil of wire is

an electro magnet

a common magnet always had

at least two poles

the direction of the force exerted on a moving charge in a magnetic field is

at right angles to the direction of the motion

like kinds of magnetic poles repel while unlike kinds of magnetic poles

attract

when a current carrying wire is bent into a loop, its magnetic field inside the loop

becomes stronger

List two ways that magnets are like electric charges

can attract and repel without touching depending which ends of the magnet are near one another strength of their interaction depends on separation distance between the two magnets

in the atoms of non ferromagnetic materials(iron), the indivual electrons

cancel one another

whereas electric charges can be isolted, magnetic poles

cannot

explain how the effect of magnetic forces on charge particles helps protect earth from cosmic radiation

charged particles from outer space are deflected by earth's magnetic field, reducing the intensity of radiation

magnetic field lines about a current carrying wire

circle the wire in closed loops

the shape of a magnetic field surrounding a current carrying conductor is

circular

what are magnetic domains

clusters of aligned atoms caused from interactions of magnetic field

what causes earth's magnet

convection current

describe some possible explanations for why earth itself is a magnet

convection currents in molten parts of earth's interior

describe a simple electromagnet

current carrying wire with many loops

describe what happens to the magnetic domains in an iron nails that is brought near a strong magnet

domains that are already oriented in that direction of magnetic field grow and domains that are not aligned with the magnet field rotate into alignment

to weaken a bar magnet

drop it, whack it, heat it

two ways to make a permanent magnet weaker

dropped heated

What happens if you break a bar magnet in half and then brea each of the laves in half

each laves will behave as a complete magnet

electric motor

each time the coil makes a half rotation, the direction of the current changes in cyclic fashion to produce continuous rotation

an iron iron is more strongly attracted to the

either the north of south pole

its due to

electric currents

which force field can increase a moving electron's speed

electric field

whihc field can accelerate an electron

electric field magnetic field

two types of electron motion that produce the magnetic field in a bar magnet

electron revolution - electrons revolve around the nucleus electron spin - electrons spin around about their own

which one is more important in terms of the materials overall magnetic field

electron spin

compared to the huge force that attracts an iron tack to a strong magnet, the force that the tack exerts on the magnet is

equally huge

direction of force that a magnetic field exerts on a moving charged particle is always perpendicular to

field lines and current

Where the magnetic field lines are close together,

field strength is great

mechanical to electric

generator

magnetic declination

geographyic and magnetic poes arent same

magnetic field is not due to a

giant magnet in interior

over geologic history the earth's magnetic field

has reversed many times

if you break a bar magnet in half youll

have two magnets

place an iron rod inside a current carrying coil of wire and you

increase the strength of the electromagnet

the most magnetic of these metals is

iron

how do rock strata provide evidence that earth's magnetic field is not stable

iron atoms in a molten state tend to align with earth's magnetic field, when iron soldifies, the direction of earth's field is indicated by orientation f the domain;s in rock

electromagnet

iron bar placed in a current carrying coil

moving charged particles cant be

isolated

particle moves int eh direction neither perpendicular nor parallel to the magnetic field line

less force

earth is a huge

magnet

discrepancy between the orientation of a compass and truth north is called the

magnetic declination

the difference between a piece of ordinary iron and an iron magnet is the alignment of the

magnetic domains

What is the name of the force due to the motion of charged particles

magnetic force

fore that acts between a pair of magnetic poles depends on

magnetic pole strength - separation distance

pigeons navigate primarily

magnetic sensors in their heads

force that acts between a pair of electrically charged particles depends on

magnitude of charge - separation distance

particle moves in a direction perpendicular to the magnetic field lines

maximum force

a current carrying wire in a magnetic field

may be deflected may experience a force

electric to mechanical

motor

magnetism is due to the motion of electrons as they

move around the nucleus and spin on their axes

source of all magnetism

moving electric charge

can magnet poles be isolated like electric poles

no

Every magnet, has a

north and south pole

the conventional direction of magnetic field lines outside a magnet are from

north to south

direction of the magnetic field outside a magnet is from the

north to south pole

if an ordinary iron nail is removed from a strong magnet, the nail will lose its magnetism Why?

ordinary thermal motion causes most or all of the domains in the nail to return to a random alignment

a beam of electrons can pass through a magnetic field without being deflected if the direction of the beam is

parallel to the field lines

a beam of electrons passing through a magnetic field experiences maximum deflection if the direction of the beam is

perpendicular l to the field lines

the force exerted on an electron moving in a magnetic field is maximum when the electron moves

perpendicular to the magnetic field

the force of a magnetic field exerts on a current carrying wire is maximum when the wire is oriented

perpendicular to the magnetic field

force on a wire is maximum when the current is

perpendicular to the magnetic field lines

Regions that produce magnetic forces are called magnetic

poles

the intensity of cosmic rays bombarding the earth's surface is most at the

poles

if a magnet produces a force on a current carrying wire, the wire

produces a force on the magnet

the lift experiences by maglev trains is due to magnetic

repulsion

earth's magnetic field

reverses direction

magnetic poles of earth are widely

separated from geographic poles

magnetic field

space around the magnet

as the number of loops in a current carrying wire is increased, the

stronger the enclosed magnetic field becomes

if the direction of current in the wire is reversed,

the deflecting force on the wire acts in the opposite direction

Where the magnetic field lines are far apart

the field strength is weak

an iron rod becomes magnetic when

the magnetic domains are alligned

why is cosmic ray bombardment greatest at earth;s magnetic poles

the rays approach the earth radially from all directions

the force on an electron moving in a magnetic field will be least when its direction is

the same as the magnetic field direction

if its calibrated to measure electric potential (voltage) is called

voltmere

particle is at rest in the field

zero force

particle moves in a direction parallel to the magnetic field lines

zero force