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Magnetism
Moving electric charges create
magnetic fields
Electrons spinning around atoms are
moving electric charges.
Usually, opposite direction spinning
electrons pair up, and cancel the
magnetic field.
Iron atoms have four unpaired
electrons that create a net magnetic
field.
Cobalt and Nickel can also become magnetic
Electrons moving in a wire create a
magnetic field
Remember electro-physics is backwards…it
assumes positive charges are moving
Right Hand Rule for Current
Velocity of a “+” charge
B is the magnetic field
strength
Drawing Magnetic Fields
Magnetic Vectors have to be shown in 3D
Velocity of
charge (+)
Magnetic
field
strength
Magnetic Force
Arrows are drawn in 2D
To draw into or out of the board,
“arrows” are also used
X is the tail of an arrow into the board
.
is the arrow coming out of the board
If this was an electron
moving in a magnetic
field…which way is it
being forced?
Formulae
Magnitude of Magnetic Field
B = F/qv
Force
velocity
charge
A wire dragged through a magnetic field…
F = BIl
l = length of wire