Electromagnetism I is an introduction to electromagnetic
fields and forces. Electromagnetic forces quite literally dominate
our everyday experience. The material object presenting this text
does not fall through the floor to the center of the earth because
it is floating on (and held together by) electrostatic force fields.
However, we are unaware of this in a visceral way, in large part
because electromagnetic forces are so enormously strong, 1040
times stronger than gravity.
Because of the strength of electromagnetic forces,
any small imbalance in net electric charge gives rise to enormous
forces that act to try to erase that imbalance.Thus in our everyday
experience, matter is by and large electrically neutral, and our
direct experience with electromagnetic phenomena is disguised by
many subtleties associated with that neutrality. This is very unlike
our direct experience with gravitational forces, which is straightforward
The objectives of this course are to tease out
the laws of electromagnetism from our everyday experience by specific
examples of how electromagnetic phenomena manifest themselves. We
want to be able: (1) to describe, in words, the ways in which various
concepts in electromagnetism come into play in particular situations;
(2) to represent these electromagnetic phenomena and fields mathematically
in those situations; (3) and to predict outcomes in other similar
situations. The overall goal is to use the scientific method to
come to understand the enormous variety of electromagnetic phenomena
in terms of a few relatively simple laws.
Why Is Understanding Electricity & Magnetism
It is essential to our understanding the
world around us. The most fundamental processes in nature,
from the forces that determine the structure of atoms and molecules
to the phenomena of light to nerve impulses in living systems, depend
on electric and magnetic fields.
It is fundamental to current and future
technologies. Motors, power generation and transmission,
electronics, sensors, and communication – both wired and wireless
– involve the manipulation of electric or magnetic fields.
There are few advances in technology that can be made without the
use of electronic circuits or electric and magnetic fields.
It is the simplest example of unification
in science. A large and diverse body of observational facts
can be explained in terms of a few simple concepts. The phenomena
of electricity and magnetism, which appear to be completely different,
are shown to be two manifestations of the same physics. The theory
requires few if any approximations. Results can be predicted with
It represents the most quantitative mode
of inquiry of all the sciences. Of the various ways to
approach science, physics in general, and E&M in particular,
starts with the smallest set of fundamental assumptions. Quantitative
rigor in solving important problems is rewarded by unprecedented
agreement with measured results. Chemistry and biology demonstrate
different, complementary approaches to dealing with natural phenomena.
Thanks to Tom Greytak & Marc Kastner