Chapter 22 Flashcards by J L

an electric field surrounds any __________

stationary electric charger

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the region of space surrounding a moving __________ includes a __________

charge

magnetic field

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a magnetic field also surrounds any material with __________

permanent magnetism

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both the electric field and magnetic field are __________

vector fields

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both the electric field and magnetic field are __________

north pole of a compass

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__________ can be used to show the field lines, as traced out by a compass, would look

magnetic field lines

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the magnetic field at some point in space can be defined in terms of the __________

magnetic force

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simlarities to electric force (with magnetic force)

the magnetic force is __________ to the __________ of the particle
the magnetic force on a __________ is directed __________ on a positive charge moving in the SAME direction
the magnetic force is __________ to the magnitude of the magnetic field vector

proportional; charge q

negative charge; opposite to the force

proportional

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TOTALLY DIFFERENT from electric force (with mag force)

the magnetic force is proportional to the __________
if the velocity vector makes an angle with the magnetic field, the magnitude of the magnetic force is __________
when a charged particle moves __________ to the magnetic field vector, the magnetic force on the charge is __________

speed v of the particle

proportional to sin(theta)

parallel; zero

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when a charged particle moves in a direction NOT PARALLEL to the magnetic field vector, the magnetic force acts in a direction __________ to both the velocity and magnetic field:

-the mag force is __________ to the plane formed by the velocity and the magnetic field

perpendicular

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when a charged particle moves in a direction NOT PARALLEL to the magnetic field vector, the magnetic force acts in a direction __________ to both the velocity and magnetic field:

-the mag force is __________ to the plane formed by the velocity and the magnetic field

perpendicular

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the magnetic force is more complicated than elec. force because:

1) it depends on the __________ of the particle
2) its direction is __________ to both velocity of the particle and the magnetic field

velocity

perpendicular

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FIRST RIGHT HAND RULE:
-the fingers point in the direction of the __________

the palm faces the __________
-curl your fingers in the direction of the field

-the thumb points in the direction of the corss product, which is the direction of __________ for a positive charge, OPPOSITE the direction for a __________ charge

velocity

magnetic field

force
negative

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FIRST RIGHT HAND RULE:
-the fingers point in the direction of the __________

the palm faces the __________
-curl your fingers in the direction of the field

-the thumb points in the direction of the corss product, which is the direction of __________ for a positive charge, OPPOSITE the direction for a __________ charge

velocity

magnetic field

force
negative

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SECOND RIGHT HAND RULE:
-thumb is the direction of the __________

fingers are in the direction of the __________
palm is in the direction of __________ for a positive particle, force on a negtive charge is __________

velocity

magnetic field

force
opposite

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the magnetic force is ZERO when the velocity and the field are __________

parallel or antiparallel

0 or 180 deg

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the magnetic force is MAXIMUM when the velocity and the magnetic field are __________

perpendicular

90 deg

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the magnetic force is MAXIMUM when the velocity and the magnetic field are __________

perpendicular

90 deg

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important differences between electric and mag forces on charged particles:

-the electric force vector is ALONG the direction of the electric field, whereas the magnetic force vector is __________ to the magnetic field

perpendicular

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important differences between electric and mag forces on charged particles:

-the electric force acts on a charged particle REGARDLESS of whether the particle is moving, whereas the magnetic force acts on a charged particle ONLY when the _________

particle is in motion

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important differences between electric and mag forces on charged particles:

-the electric force DOES WORK in displacing a charged particle, whereas the magnetic force associated with a STEADY magnetic field does _______ when a particle is displaced

no work

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angular speed is also referred to as the _______

cyclotron frequency

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angular speed is also referred to as the _______

cyclotron frequency

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the angular speed of the particle and the period T of the circular motion __________ on the translational SPEED of the particle or the _______ of the orbit for a given particle in a given uniform mag field

do not depend

radius

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do not depend | radius

if a charged particle moves in a magnetic field at some arbitrary ANGLE with respect to the field, its path is a _______

helix

in many applications, the charged particle will move in the presence of both _______ and _______

magnetic | electric fields

in physics exp involving moving charged particles, it is important that ALL particles move with essentially the _______ -can be achieved by applying a combination of an _______ and _______

same velocity electric magnetic field

when the magnitudes of the two fields are chosen so that qE = qvB, the charged particle is modeled as a _______ and moves in a straight _______ line through the region of the fields

particle in equilibrium | vertical

a _______ separates ions according to their mass-to-charge ratio - a beam of ions passes through a _______ selector and enters a _______ magnetic field - after entering the second mag field, the ions move in semicircle before striking a detector.... if the ions are POSITIVELY charged they deflect _______, if the ions are NEGATIVELY charged they deflect _______

mass spectrometer velocity second left right

a _______ is a device that can accelerate charged particles to very high speeds -the particles produced are used to bombard atomic nuclei and therby produce reactions, which are anaylzed by researchers

cyclotron

hospitals use cyclotrons: - to produce _______ for diagnosis and treatment - use beams of high energy particles for treating _______

radioactive substances | cancer

a current-carrying conductor experiences a force when placed in an external _______ -the current represents a collection of many _______ in _______

mag field | charged particles; motion

maximum value of torque only occurs when the field is _______ to the plane of the loop***

parallel

torque has a MAXIMUM value when the field is _______ to the normal plane of the loop (theta = _______)***

perpendicular, 90

torque has a MAXIMUM value when the field is _______ to the normal plane of the loop (theta = _______)***

perpendicular, 90

the torque is ZERO when the field is _______ to the normal to the plane of the loop

parallel

RIGHT HAND RULE CAN BE USED TO DETERMINE THE DIRECTION OF THE AREA VECTOR: - curl your fingers in the direction of the _______ in the loop - your thumb points in the direction of the _______

current area vector

the system has its lowest energy when the MAGNETIC MOMENT (dipole) and the MAGNETIC FIELD point in the _______ direction, and highest energy when they point in _______ directions

same | opposite

current acts as a _______ of a mag field

source

there are TWO SIMILARITIES between the BIOT-SAVART LAW of magn and the equation for the ELECTRIC FIELD of a charge distribution: - the current element produces a _______, and the charge element produces an _______ - the magnitude of the magnetic and electric fields vary as the _______ of the distance from the source

mag field elec field inverse square

there are TWO DIFFERENCES between the BIOT-SAVART LAW of magn and the equation for the ELECTRIC FIELD of a charge distribution: - the electric field created by a point charge is _______ in direction - the mag field created by a current element is _______ to both the length element and the unit vector - an elec field can be a result either of a _______ or a _______ of charges, but a mag field can only be a result of a _______

radial perpendicular single charge; distribution current distribution

parallel conductors carrying currents in the SAME direction _______

attract each other

parallel conductors carrying currents in OPPOSITE directions _______

repel each other

the magnetic force between two parallel current-carrying wires is used to define the _______

ampere

the magnetic force between two parallel current-carrying wires is used to define the _______

ampere

even though ampere's law is TRUE for all _______ configuarations, it is only useful for calculating the magnetic fields of configurations with _______

high degrees of symmetry

even though ampere's law is TRUE for all _______ configuarations, it is only useful for calculating the magnetic fields of configurations with _______

high degrees of symmetry

to use ampere's law, the path of integration (amperian loop) must satisfy ONE OR MORE of the following: 1) the value of mag field can be argued by symmetry to be _______ over the portion of the path 2) the dot product can be expressed as a simple algebraic product Bds because the field and length element are _______ 3) the dot product is _______ because the field and length element are _______ 4) the mag field can be argued to be _______ at all points on the portion of the path

constant parallel zero; perpendicular zero

a _______ is a long wire wound in the form of a helix - each of the turns can be modeled as a _______ - the net mag field is the vector sum of all the fields due to all the turns

solenoid | circular loop

as the length of the solenoid increases, the field within it becomes more _______

uniform

as the length of the solenoid increases, the field within it becomes more _______

uniform

for an IDEAL solenoid: - the turns are _______ - the length is much _______ than the radius of the _______ - the field outside of solenoid is _______ - the field inside is _______

closely spaced greater; turns negligible uniform

for an IDEAL solenoid: - the turns are _______ - the length is much _______ than the radius of the _______ - the field outside of solenoid is _______ - the field inside is _______

closely spaced greater; turns negligible uniform

bohr structural model of the atom: -electrons are assumed to move in _______ about the much more massive nuclues -each orbiting electron is viewed as a _______ with a corresponding _______

circular orbits tiny current loop magnetic moment

the magnetic moment of one electron in an atom is canceled by that of another electron in the atom, orbiting in the _______

opposite direction

an electron has _______, called SPIN | -the spin of an electron is an _______ separate from its orbital angular momentum

intrinsic angular momentum | angular moment

an atom with an _______ number of electrons must have at least one _______ electron and a corresponding spin magnetic moment

odd | "unpaired"

_______ substances contain atoms with spin magnetic moments that tend to allign PARALLEL to each other even in a weak external mag field

ferromagnetic

all ferromagnetic materials contain microscopic regions called _______, within which all magnetic moments are sligned

domains

the boundaries between ferromagnetic domains having different orientations are called _______

domain walls

in an unmagnetized sample, the domains are _______ so that the net magnetic moment is _______

randomly oriented | zero

the extent to which a ferromagnetic substance retains its magnetism is described as being magnetically _______ or _______

hard | soft

soft magnetic materials, such as iron, are easily magnetized but also tend to _______

lose their magnetism easily

when a _______ is magnetized and the externall magnetic field is REMOVED, thermal agitation produces domain motion and the material quickly returns to an _______

unmagnetized state

_______, such as cobalt and nickel, are difficult to magnetize but tend to _______, and domain alignment persists in them are the external magnetic field is _______

hard magnetic materials retain their magnetism remove

hard magnetic materials are referred to as _______

permanent magnets

when a sample is placed in an external magnetic field, domains with magnetic moment vectors intially oriented along the external field _______, resulting is MAGNETIZED SAMPLE when external field is removed, the sample may retain most of its _______

grow magnetism

Chapter 22 Flashcards

(69 cards)