Chapter 10 Flashcards
What is an object capable of attracting materials such as iron or steel by a magnetic force?
magnet
What is the property of attracting objects by the magnetic force?
magnetism
What is the regions of concentrated magnetism in a magnet?
pole
What is the pole of a magnet that points north?
north pole
What is the pole of a magnet that points south?
south pole
What is the law stating that unlike poles attract and like poles repel?
law of magnetic poles
What is the region surrounding a magnet in which other objects are affected by magnetism?
magnetic field
What are the imaginary lines that indicate the direction and the strength of a magnetic field?
lines of flux
What is the law stating that the force between two magnetic poles is directly related to the product of the pole strength and inversely related to the square of the distance between the poles?
law of magnetic force
What is the extent to which a material can absorb or channel lines of magnetic force?
permeability
How are magnetic fields produced?
by the motion of electrons and other charged particles
What is the most important cause of magnetism in magnetic materials?
electron spin
What is a group of aligned atoms having a single magnetic field?
domain
What describes substances that have no unpaired electrons and are always slightly repelled by either pole of a magnet?
diamagnetic
What is the theory that states that the magnetic field of a magnet is the sum of thousands of magnetic domians?
domain theory
What describes substances that have only one unpaired electron and are weakly attracted to magnets?
paramagnetic
What describes substances that have several unpaired electrons and are strongly attracted to magnets?
ferromagnetic
What describes substances that can be quickly magnetized even in a weak magnetic field?
magnetically soft
What describes materials whose domains strongly resist changes in the direction of their magnetic fields?
magnetically hard
What is a magnets made from magnetically hard material?
permanent magent
What is a magnet made from magnetically soft material?
temporary magnet
What is magnetizing by stroking an object with a magnet?
magnetizing by contact
What is temporary magnetization caused by placing an object within a magnetic field?
magnetizing by induction
What is magnetizing caused around a wire by electricity flowing through a wire?
magnetizing by electricity
What is a device that produces a strong magnetic field when electricity passes through it?
electromagnet
What is the rule stating that if the thumb of the left hand is pointed along a wire in the direction of electron current, the fingers encircle the conductor in the direction of the generated magnetic field?
left-hand rule
What is a magnetically soft material placed within the coils of an electromagnet in order to strengthen its field?
core
What is the temperature at which a ferromagnetic material’s domains disappear?
Curie point
What is the resistance of a magnet to being demagnetized by a magnetic field?
coercivity
What is the force on an electric charge moving in a magnetic field that causes the charge to deviate from its original path?
deflecting force
What is a navigational device consisting of a magnet free to swing horizontally so that it always points north?
magnetic compass
Who was a British pioneer of electrostatics and discovered that a compass points north because it is guided by Earth’s magnetic field?
William Gilbert
What is the book in which William Gilbert published his findings on magnetism?
De Magnete
What is the geographically north magnetic pole of the earth; a “south-seeking” pole?
north magnetic pole
What is the geographically south magnetic pole of the earth; a “north-seeking” pole?
south magnetic pole
Do the magnetic poles of the earth coincide exactly with the geographic poles?
no
If the earth’s magnetic poles are no called north and south because of their magnetic properties, what are they named for?
their geographic locations
What is the direction to the earth’s geographic north pole considered to be?
true north
What is the deviation of a compass needle from true north?
angle of declination
What is a line connecting points of equal declination?
isogonic line
What is a line connecting all points where a compass needle points true north?
agonic line
What is the phenomenon in which a compass constructed with a magnet that swings vertically instead of horizontally points in the angle at which lines of flux enters the earth?
inclination
What is a line connecting points of equal inclination?
isoclinic lines
What is an isoclinic line where the angle of inclination is 0°?
magnetic equator
What is the extent of a planet’s magnetic field in space?
magnetosphere
What is a stream of plasma that emanates from the sun?
solar wind
What is the portion of a magnetosphere that stretched out away from the sun?
magnetotail
What is the outer boundary of the magnetoshpere?
magnetopause
What are two vast, doughnut-shaped belts of high-speed charged particles surrounding Earth?
Van Allen radiation belts
What is the display of shimmering light produced by high-speed particles that spiral into the upper atmosphere and crash into molecules of air?
auroras
What is another name for the northern lights?
aurora borealis
What is another name for the southern lights?
aurora australis
Is Earth the only natural magnet in the solar system?
no
