magnetism Flashcards
where objects are attracted or repelled to one another
magnetism
● magnetic oxide of iron
● rod-like stone that when suspended by a
string, it rotates back and forth.
● most magnetic of all naturally occurring
minerals on earth.
magnetite
● accumulation of many atomic magnets with their dipoles aligned
● If all of these magnetic domain aligned, it will create a magnet
magnetic domain
● nuclear magnetic dipole
● rotates on its own axis and produces
magnetic field
magnetic moment
● ability of a material to attract the lines of magnetic field density
● refers to a material’s ability to absorb magnetic flux (change)
magnetic permeability
● degree to which a material can be magnetized
● ability of a material to become magnetized by an external magnetic field
magnetic susceptibility
classification of magnets
natura magnet
artificial magnet
electromagnet
- magnets that occur in nature.
- best example is EARTH
natural magnet
- Strong magnetic fields that do not fade.
- Man-made
artificial magnet
best example of artificial magnet
magnetic compass
● temporary magnets produced by means of an electric current.
● magnets that run on electricity
● simply the coils of wire usually wrapped
around an iron core.
● strength of magnetic field is directly
proportional to the amount of current
electromagnet
coil of wire
solenoid
4 magnetic states of matter
non magnetic
ferromagnetic
paramagnetic
diamagnetic
unaffected when brought into the magnetic field.
non magnetic
ex of non magnetic
wood and glass
● have a large, positive susceptibility to an external magnetic field
● exhibit strong attraction to magnetic field
● made by human
ferromagnetic
ex of ferromagnetic
iron, alnico
● lies somewhere within ferromagnets and diamagnets.
● Does not retain the magnetic properties when an external field is removed
paramagnetic
ex of paramagnetic, used as main component of contrast agent in MRI
gadolinium
weakly repelled from both poles of a magnetic field.
diamagnetic
ex of diamagnetic
water and plastic
magnetic laws
dipole
attraction and repulsion
induction
magnetic force
states that dividing a magnet into smaller pieces will only create small magnets with north and south poles
dipole
proportional to the product of the magnetic pole strengths divided by the square of the distance between them
magnetic force
electrostatic charge can be
induced from one material to another, so some materials can be made by induction
induction
SI unit of magnesium field strength
tesla
older SI unit of magnesium field strength
gauss
The earth’s magnetic field strength is approximately __ at the equator in both poles __
50uT, 100uT
● observed that the legs of the frog twitched during dissection when two metals touched.
Luigi Galvanni
● invented Voltaic Pile
● First “wet cell battery”
● Sandwiched Zn and Cu
Alessandro Volta
● discovered that the electric current creates a magnetic field.
● Any charged particle in motion induces a magnetic field
Hans Oersted
● Credited the discovery of induction in 1831
● Concluded that the magnetic field cant be used to generate electric current.
● Made the first dynamo in 1837
Michael Faraday
states that the direction of the induced current opposes the action that induces it.
Heinrich Lenz, Lenz Law
● Practical application of Faraday’s law.
● A device that converts mechanical
energy to electrical energy
● Can be called energy converter
electric generator
● Practical application of Oersted Discovery.
● Transform Electrical Energy to Mechanical Energy
electric motor
