The following sections of this BookRags Literature Study Guide is offprint from Gale's For Students Series: Presenting Analysis, Context, and Criticism on Commonly Studied Works: Introduction, Author Biography, Plot Summary, Characters, Themes, Style, Historical Context, Critical Overview, Criticism and Critical Essays, Media Adaptations, Topics for Further Study, Compare & Contrast, What Do I Read Next?, For Further Study, and Sources.
(c)1998-2002; (c)2002 by Gale. Gale is an imprint of The Gale Group, Inc., a division of Thomson Learning, Inc. Gale and Design and Thomson Learning are trademarks used herein under license.
The following sections, if they exist, are offprint from Beacham's Encyclopedia of Popular Fiction: "Social Concerns", "Thematic Overview", "Techniques", "Literary Precedents", "Key Questions", "Related Titles", "Adaptations", "Related Web Sites". (c)1994-2005, by Walton Beacham.
The following sections, if they exist, are offprint from Beacham's Guide to Literature for Young Adults: "About the Author", "Overview", "Setting", "Literary Qualities", "Social Sensitivity", "Topics for Discussion", "Ideas for Reports and Papers". (c)1994-2005, by Walton Beacham.
All other sections in this Literature Study Guide are owned and copyrighted by BookRags, Inc.
Any current circulating in a planar loop produces a magnetic moment whose magnitude is equal to the product of the current and the area of the loop. When any charged particle is rotating, it behaves like a current loop with a magnetic moment. For a system of charges, the magnetic moment is determined by summing the individual contributions of each charge-mass-radius component.
It turns out that, both classically and quantum mechanically, there is a close connection between a particle's magnetic moment and its angular momentum. (The angular momentum of a particle moving in a circle is equal to the product of the particle's linear momentum and its perpendicular distance from the axis of revolution.) Classically, for the charged particle moving in a circle, the size of the magnetic moment is proportional to the magnitude of the particle's angular momentum. In quantum mechanics, angular momentum is quantized, i.e., it only assumes discrete values instead of the continuous range of possible values predicted by classical theory. A consequence of quantum theory and the quantization of angular momentum is that the magnetic moment also must be quantized.
The magnetic properties of matter can be thought of as arising from microscopic atomic currents that produce magnetic moments in that matter. In paramagnetic materials, permanent magnetic moments arise from the intrinsic angular momentum (spin) of individual electrons. In the absence of an applied magnetic field, these magnetic moments are randomly arranged, and there is no net magnetic moment. An applied magnetic field, however, aligns the moments in the field direction. In diamagnetic materials, all intrinsic magnetic moments are cancelled out by the pairing of electrons. Any remaining magnetic effects in diamagnetic materials are produced by the orbiting electrons.