PHYS102: Introduction to Electromagnetism

The physics of our universe is dominated by four fundamental forces: gravity, electromagnetism, and weak and strong nuclear forces. These forces control how matter, energy, space, and time interact. For example, when someone sits on a chair, gravitational forces balance with the material forces that "push up" to hold the person in place. This upward push results from electromagnetic forces on microscopic length scales. On the larger stage, gravity holds the celestial bodies in their orbits, but without electromagnetic radiation (light), none of these bodies would be visible to us.

Electromagnetism extends our understanding beyond classical mechanics because it introduces the concept of charge – a property we can observe in macroscopic objects and the smallest building blocks of matter. Electromagnetism is the invisible hand that allows charged objects to interact with each other. It also allows you to take this course: the modern world would be impossible without telecommunications and microelectronics, two of the major applications of electromagnetism.

Scientists began studying electromagnetism in the 18th century. They prepared the groundwork for developments in the 20th century and our modern understanding of atomic structure and the cosmos. In this course, we will learn why electromagnetism is so important for everyday applications and fundamental physics. To put this information into proper context, you should be familiar with the force concept of classical mechanics.

Building on the idea of force, we develop the more abstract concept of fields. This study culminates in Maxwell's theory which, among other achievements, led to the discovery of radio waves. We begin by discussing waves and oscillations in the more familiar setting of mechanics to review how forces relate to the motion of objects. This preparation will help you understand Maxwell's insights into the nature of electromagnetic radiation as a wave phenomenon.

The term electromagnetism combines two effects we will study separately: electricity and magnetism. We explore electrical measurements and circuits to learn how to observe, quantify, and apply the laws that govern how charges cause static electricity and magnetism. In Maxwell's equations, we will finally unify electric and magnetic effects and discover electromagnetic radiation. This will also put radio waves on the same footing as light: they are the same phenomenon, differing only in their wavelength.

In the final units of this course, we look at optics and Einstein's theory of special relativity. You can think of optics, the science of light, as a practical application of electromagnetism. However, the theory of relativity is an entirely new way of looking at the nature of space and time. This paradigm shift in the foundations of physics was inspired directly by the discoveries at the heart of this course.