Conceptual Physics Chapter 36 Magnetism – Flashcards
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what do electric charges have to do with magnetic poles?
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both attract and repel
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what is a major difference between electric charges and magnetic poles
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charges can be isolated unlike poles
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every spinning electron is a tiny magnet, since all atoms have spinning electrons why aren't they all magnets?
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electrons spin in opposite direction so their fields cancel
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what is so special about iron that makes each iron atom a tiny magnet
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fields of iron electrons don't entirely cancel
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what is magnetic domain?
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a cluster of aligned atoms
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why do some pieces of iron behave as a magnet while others don't
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domains in some are aligned
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how can a piece of iron be induced to become a magnet? why does a paper clip near a magnet become a magnet?
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the domains align and will remain that way
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why does dropping or heating weaken a magnet?
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it jostles the domains out of alignment
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what is the shape of a magnetic field that surrounds a current-carrying wire?
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concentric circles
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if a current-carrying wire is bent into a loop why is the magnetic field stronger inside the loop than outside
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fields inside loop overlap
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what must a charged particle be doing in order to experience a magnetic force?
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moving across magnetic field lines
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what must a charged particle be doing to experience magnetic force?
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moving across magnetic field lines
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which respect to an electric and magnet field how does the direction of a magnetic force on a charged particle differ from the direction of the electric force?
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magnetic is perpendicular to field, electric is parallel
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what role does earth's magnetic field play in a cosmic ray bombardment?
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deflects a lot of charged particles from outer space
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how does the direction in which current-carrying wire is forced when in a magnetic field compare with direction that moving charges are forced?
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forced the same way
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how do the concepts of force, field, and current relate to galvanometer?
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force acts on the current in the field and deflect the galvanometer coil
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why is it important that the current in the armature of a motor that uses a permanent magnet periodically change direction?
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so it rotates more than 180 degrees
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what is meant by the magnetic declination?
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difference between geographic and magnetic north
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according to most geophysicist what is the probable cause of earth's magnetic field?
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current inside the earth
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what are magnetic pole reversals, and what evidence is there that it's happened to earth
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switching of magnetic north to south and vice versa, the magnetism in earth's strata
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what kind of field surrounds a stationary electric charge? moving?
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electric, electric and magnetic
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why can iron be made to behave as a magnet, while wood cannot?
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iron, unlike wood, has magnetic domains that can be manipulated
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since iron filings aren't magnets, by what mechanism do they align themselves with magnetic filed?
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induced by aligning with external magnetic field lines, produces poles which are acted on external field creating torque in filing
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strong magnet and weak magnet attract each other, which exerts stronger force?
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neither, equal and opposite force
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why will the magnetic field strength be further increased inside a current-carrying coil if a piece of iron is place in the coil?
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alignment of domains adds to field strength
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why can a magnetic field deflect a beam of electrons but can't do work on them to speed them up?
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no component of magnetic force in the direction of motion
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how does pigeons having multiple domain magnetite magnets within their skull help them navigate?
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helps them sense direction in earth's magnetic field
