PHY122_L09 - PHY122 Physics for the Life Sciences II...

Info iconThis preview shows pages 1–6. Sign up to view the full content.

View Full Document Right Arrow Icon
Lecture 9 1 PHY122 – Physics for the Life Sciences II Lecture 9 Magnetism Note: Clicker Channel 21 10/04/2010
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Chapter 24 - Overview • Magnets and Magnetic Fields • Currents as Sources of the Magnetic Field – Current in a straight wire – Current Loop: B at center of the loop – Solenoid •t h e Magnetic Force – the force from a Magnetic Field: – on moving charges – on currents: • on a straight wire: the force between two wires … • on a current loop • Ferromagnetism • Applications: – the electric Motor –Loudspeaker –MRI 10/04/2010 Lecture 9 3
Background image of page 2
Lecture 9 4 Magnetism MAGNETISM , like electricity, is yet another force that has been known for a very long time. – The name stems from magnetite, a naturally magnetic mineral. We now know that magnetism is the action-at-a-distance force felt between currents , i.e. moving charges: – magnetic materials contain currents, in the form of rapidly spinning and orbiting electrons and nucleons, which “align” to create a macroscopic MAGNETIC FIELD B – because the magnetic forces are between (moving) charges, there must be a deep relationship with electricity… –Because motion is dependent on the reference frame of the observer, we expect connections with relativity as well… Again, we use the FIELD concept: – Magnets and Currents (the SOURCES of B ) generate a Magnetic Field B everywhere in space, –and B interacts with the “test”-magnets or “test”-currents … 10/04/2010
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
the Magnetic Field at a certain location … 10/04/2010 Lecture 9 5 A. B. C. D. 20% 23% 16% 41% A. depends on the distribution of currents in wires everywhere B. depends of the distribution of currents and magnets everywhere C. depends on the local distribution of magnets D. depends on the local distribution of currents
Background image of page 4
Magnets and Magnetic Fields Like the Electric Field, dipole field … we may visualize the magnetic field of a magnet using small magnetized snippets; e.g. iron filings –the magnetic field induces a magnetization in the filings and the magnetized filings align with this field.
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 6
This is the end of the preview. Sign up to access the rest of the document.

This document was uploaded on 12/22/2011.

Page1 / 16

PHY122_L09 - PHY122 Physics for the Life Sciences II...

This preview shows document pages 1 - 6. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online