69 terms

Honors Physics Chapter 19

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magnetic domains
a region composed of a group of atoms whose magnetic fields are aligned in the same direction
magnetic field
a region where a magnetic force can be detected
solenoid
a coil of wire with an electric current in it
North (N) to South (S)
field lines drawn from
50μT
magnetic strength of the earth
Lodestone
First discovered magnet by ancient Greeks
temporary magnet
Magnets can polarize non-magnetic materials - making a
Permanent magnets
are created from other magnets - its atomic structure makes it "hold" its magnetism
aluminum, nickel, and cobalt (called ALNICO)
Many permanent magnets are made of a combination of
tiny electromagnet
Each electron in a magnet acts like a
domains
Electrons are grouped together in
Unmagnetized
_____ domains are randomly arranged
Magnetized domains
are electrons spinning in the same direction
polarized
magnets are _____ they have two opposite ends, North and South
attract
Unlike poles
repel
Like poles
Monopoles
_____ don't exist
south magnetic pole
The geographic north pole of Earth is actually a
distance
Like electric charge, magnetic forces can work at a
Magnetic Fields
exist around the ends of a magnet
Magnetic Fields
Have both a magnitude and vector
Magnetic Fields
Drawn from N to S
Magnetic Flux
number of field lines per unit area and denotes field strength
Magnetic Flux
Helps define the strength of a magnetic field - number of field lines in a particular area around a magnetic
Magnetic Flux
ϕM = Aβcosθ
phi
represents magnetic flux
A
area of material generating magnetic field
β
magnetic field strength
stronger
A magnetic with a greater flux value is ______ than one with a lower flux value
Hans Christian Oersted
1820, _______ discovered that current in a wire moves a compass needle
perpendicular
The compass needle pointed_____ to the wire's current flow
First Right-Hand Rule
Used to determine the direction of a magnetic field
Thumb
____ points in direction of current flow (first hand rule)
The curl of your fingers
_____ indicates magnetic field direction(first hand rule)
walking & talking
thumb does the ____ and fingers do the____ (first hand rule)
Solenoids
Coil of wire with many loops
strong magnetic field
Center of soleniod makes a _____, like that of a temporary magnet
electromagnet
The magnet created by this flow is called an
stronger magnet
Higher current =
stronger magnetic field
Increasing loops =
magnetized
A metal rod placed inside the coil will become
Second Right-Hand Rule
Determines the direction of a magnetic field created by a solenoid
talking & walking
thumb does the ____ and fingers do the ____ (Second Right-Hand Rule)
magnetic field direction
thumb shows____ (Second Right-Hand Rule)
current flow
fingers show _____(Second Right-Hand Rule)
magnetic field
Current in a wire causes
forces
Magnetic fields create
perpendicular
Forces on Currents in a Magnetic Field are all ____ to each other
attracted/repelled
Wires can then be
repulsion
Opposite current direction causes
circular path
A charge moving through a magnetic field follows a
q
charge (C)
v
velocity of the charge (m/s)
β
magnetic field (T)
I
current (A)
l
length of wire (m)
Β
magnetic field (T, tesla)
Third Right Hand Rule
Used to determine the force on a current-carrying wire in a magnetic field (β)
β
Index finger (Third Right Hand Rule)
I
Thumb (Third Right Hand Rule)
F on the wire
Middle finger/palm (Third Right Hand Rule)
Third Right Hand Rule
Only for positive charges
Third Right Hand Rule
gun positioning
Circle with an X
Force into the page
Circle with a dot
Force out of the page
Galvanometers
Measures small current
Galvanometers
Uses the force from the magnetic field produced by current in wire to move a needle for reading I or V
north
south