Physics ch 18,21 test

What did Ben Franklin believe in regards to electric charge ?
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What does diamagnetic mean ?- all electrons are paired, not attracted by magnets. - magnetic permeability less than 1.What does paramagnetic mean ?- unpaired electrons, slightly attracted to magnets. - magnetic permeability slightly greater than 1.What does ferromagnetic mean?- A material strongly attracted to a magnet - magnetic permeability much greater than 1.What are conductors?- Materials that have free electrons. - allows the easy transmission of thermal energy or electricity.What are insulators?- Materials that contain atoms that have a very tight hold on their electrons. - it does not easily conduct thermal energy or electricity.What are semiconductors?Materials that can act as either conductors or insulators made from silicon in sand.What did Robert Millikan do ?- Oil drop experiment.What did J.J. Thompson do ?Demonstrated with cathode rays that all matter contains tiny negatively charged particles with same charge-to-mass ratio.What are free electrons?They are not connected to any atoms or ions and are therefore allowed to move around freely. They move when under the influence of an applied electric or magnetic field.How many poles does a magnet have?2, north and southWhat is a magnetic field?A region where other magnets or magnetic materials experience a force.What are lodestones?A natural magnet of an iron oxide ore.What are sun spots?A local magnetic field on the Sun that appears like a dark spot.What are the Van Allen belts?The Van Allen belts are two rings of ionized atoms and electrons trapped in the Earth's magnetosphere.What is the magnetosphere?The region of Earth's magnetic field shaped by the solar wind.What is an Aurora ?A polar light display resulting from the interaction between high-energy charged particles trapped in the earth's magnetic field and upper atmospheric gas molecules.What is conduction?The flow of thermal energy from one object to another through contact.What is induction?Creating a temporary electrical dipolar charged condition in a neutral object by causing a segregation of charges with a nearby source of charge.What is the law of magnetic poles?Like poles repel each other, opposite poles attract each other.What is the law of charges?like charges repel, opposite charges attractWho came up with the term magnet ?The RomansWhat was the oil drop experiment?He assumed that tiny oil drops would reach terminal velocity in air when falling due to gravity and, if charged, they could also reach terminal velocity in air when falling upward in an electrical fieldWhat is amber ?fossilized tree sapHow do we measure the strength of a magnetic field ?Magnetic field vector (B)What did Robert Boyle do ?First person to perform quantitative experiments.Who was George Stoney?Who named the negatively charged particles as electronsWhat is the relationship between temperature and magnetic field strength?Heating the magnet cause its molecules to become more disorderly.How do we measure the strength of a charge ?What does virtuous mean ?strength or forceWhat does resinous mean?Electrical behavior like that of amber or other resinous materials, which acquire a negative charge when rubbed with fur.How does an electroscope work ?when the electroscope is NOT CHARGED, the leave hang STRAIGHT DOWN. when the electroscope IS CHARGED, the leaves SPREAD APART because they are repelling each other.What is an electrical ground?A path for electric current to follow to the ground.What are central forces ?The force that is directed along the line joining the object and the origin.What are conservative forces?They are path independent forces that do not dissipate the mechanical energy of a system. * if only conservative forces are acting on an object, the total mechanical energy is conserved. * examples gravity and electrostatic forces.What is static electricity?Atoms build up extra electrons & they are ready to jump to the next atomWhat are magnetic field lines?lines that map out the magnetic field around a magnet.