science Flashcards
magnet
any object that attracts the metal iron
magnetic pole
a place on a magnet where the force it applies is strongest
magnetic force
a force of attraction or repulsion between the poles of two magnets
attraction
when opposite poles of two magnets are near each other the resulting magnetic field applies a force of attraction
repulsion
when two like poles of two magnets are near each other the resulting magnetic field applies a force of repulsion
what does an invisible magnetic field do
surrounds all magnets, it is this magnetic field that applies forces on other magnets
what do iron fillings do
form a pattern of curved lines that reveal the magnet’s magnetic field
how can a magnets magnetic field be represented
lines, called magnetic field lines
where is the magnetic force the strongest
magnetic poles (where the lines are closest together)
how do the field and force become weaker
when the field lines become farther apart
what happens to the magnetic fields around two bar magnets that are brought together
the two fields combine and form one new magnetic field
how to the magnets repel
if similar poles of two magnets such as north and north or south and south are Brough near each other the magnets repel
what happens if the North Pole of one magnet is Brought near the South Pole of another magnet
the two magnets attract (the magnets will pull together)
similar poles _____, opposite poles _____
repel, attract
how does a magnetic force become stronger
as magnets move closer together
how does a magnetic force become weaker
as magnets move father apart
there are two magnetic poles on all magnets. what are they
North Pole and south pole
what happens when magnetic fields combine
they form field lines with different patterns
what do the new patterns (of field lines) depend on
whether the magnets are attracting or repelling each other
why does earth have a magnetic field
due to molten iron and nickel in its outer core
like magnets earth has what
north and south magnetic poles
a compass needle doesn’t point directly towards what
the poles of a magnet
What do the needles of a compass align with
the field lines and points in the direction of the field lines
How do auroras occur
a magnetic field surrounds earth. sometimes large numbers of particles from the sun travel along earth’s magnetic field lines and concentrate near the magnetic poles. There the particles collide with atoms of gases in the atmosphere causing the atmosphere to glow
magnetic material
any material the is strongly attracted to a magnet
ferromagnetic elements
elements including iron, nickel, and cobalt, that have an especially strong attraction to magnets
what does a magnetic field surround
every atom that makes up all materials
magnetic domain
a region in a magnetic material in which the magnetic fields of the atoms all point in the same direction
what happens when the fields around the atoms combine
they cancel each other
most types of matter are ________ materials and are not attracted to ________
nonmagnetic, magnetics
magnetic domain
a region in a magnetic material in which the magnetic fields of the atoms all point in the same direction
what do magnetic fields of the atoms in a domain combine
a single field around the domain
what directions do the magnetic fields of their domains point at
random directions
what does an object need to be to be a magnet
its magnetic domains must align
what causes to object to become a magnet
when the domains align their magnetic fields combine, forming a single magnetic field around the entire material
temporary magnet
a magnet that quickly loses its magnetic field after being removed from a magnetic field
permanent magnet
the magnet that remains a magnet after being removed from another magnetic field
what are objects made of magnetic materials attracted to
magnets
electromagnetic
a magnet created by wrapping a current-carrying wire around a ferromagnetic core
how does a core become a magnet
when an electric current flows through the coil
how does the strength of the magnetic field around a current-carrying wire increase
when the wore is wound into a coil
how do the magnetic field around the wire become stronger
the magnetic fields around the individual lips of the coil combine
how is an electromagnet made
by placing a ferromagnetic material as a core within the wire coil
example of a ferromagnetic material
iron, cobalt, and nikel
how do you turn off the magnetic field around an electromagnet
by turning off the current
how do you strengthen the magnetic force
increasing the electric current in the coil
what does the strength of the magnetic force of an electromagnet depend on
the number of loops in the electromagnet’s wire coil
how do you reverse an electromagnet’s north and south magnetic poles
changing the direction of the current in the wire coil
electric motor
a device that uses an electric current to produce motion
what is an electromagnet
a magnetic core within a current carrying wire coil
how does an electric motor rotate
alternating attraction and repulsion between a permanent magnet and an electromagnet
electric generator
a device that uses a magnetic field to transform mechanical energy to electric energy
direct current
an electric current that flows in one direction
alternating current
an electric current that changes direction in a regular pattern
what happens when a wire moves through a magnetic field
an electric current is produced in the circuit
there is no ______ when the coil is not moving
current
turbine
a shaft with a set of blades that spins when a stream of pressurized fluid strikes the blades
what happens when a turbine connects to an electric generator
it will spin as steam is forced through its blades
how to do math problem
Vs = Vp X (Ns / Np)
Np
number of loops on primary coil
Ns
number of loops on secondary coil
Vp
input voltage to primary coil
Vs
output voltage from secondary coil
what do power plants do
move electric energy through long-distance wires
what do transformers do
raise and lower the voltage of the current as needed by homes and businesses
what do electric generators do
transform mechanical energy to electric energy
a magnetic field can produce what
electric current
an electric current produces what
a magnetic field
what turns an electric generator
steam or another source
what does a step-up transformer do
increase the voltage for transmission
what does a supply step-down transformer do
lowers the voltage to 120 V
what does a step-down transformer do
decreases the voltage going into a neighborhood
