Prozorov_10 - PHYSICS 222 Introduction to Classical Physics...

PHYSICS 222
Introduction to Classical Physics II
Prof. Ruslan Prozorov
Iowa State University
Fall 2011
LECTURE 10
Magnetic field
Sources of magnetic field
Magnetic forces

magnetism
Here you see an MRI
scans. The magnetic
field interacts with
molecules in the body
to orient spin before
radio frequencies are
used to make the
spectroscopic map.
The different shades
are a result of the
range of responses
from different types
of tissue in the body.
o Magnets exert forces on each other just like charges. In
fact, you can draw magnetic field lines just like you drew
electric field lines.
o We will soon discover is that electrostatics,
electrodynamics, and magnetism are deeply interwoven.
14 September 2011 PHYS222 - Lecture 10 - Prof. Ruslan Prozorov - Iowa State University 2

Magnetic north and south poles’ behavior is not
unlike electric charges. For magnets, like poles
repel and opposite poles attract.
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magnetism and (some) metals
A permanent magnet
will attract a metal like
iron, cobalt, nickel with
either the north or south
pole.
Other metals, like
aluminum, gold, copper,
silver are not attracted.
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magnetism of our planet
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how compasses work
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magnetosphere shield
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magnetic field variation
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units of magnetic field
• - magnetic field strength: [A/m]
• - magnetic induction: [T] (Tesla)
• in the simplest case:
• magnetic permeability of free space
•  - relative magnetic permeability
14 September 2011 PHYS222 - Lecture 10 - Prof. Ruslan Prozorov - Iowa State University 9
0
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