0Introduction

IB Electromagnetism

0 Introduction

Electromagnetism is one of the four fundamental forces of the universe. Apart

from gravity, most daily phenomena can be explained by electromagnetism. The

very existence of atoms requires the electric force (plus weird quantum effects)

to hold electrons to the nucleus, and molecules are formed again due to electric

forces between atoms. More macroscopically, electricity powers all our electrical

appliances (by definition), while the magnetic force makes things stick on our

fridge. Finally, it is the force that gives rise to light, and allows us to see things.

While it seems to be responsible for so many effects, the modern classical

description of electromagnetism is rather simple. It is captured by merely four

short and concise equations known as Maxwell’s equations. In fact, in the

majority of this course, we would simply be exploring different solutions to these

equations.

Historically, electromagnetism has another significance — it led to Einstein’s

discovery of special relativity. At the end of the course, we will look at how

Maxwell’s equations naturally fit in nicely in the framework of relativity. Written

relativistically, Maxwell’s equation look much simpler and more elegant. We will

discover that magnetism is entirely a relativistic effect, and makes sense only in

the context of relativity.

As we move to the world of special relativity, not only do we get a better

understanding of Maxwell’s equation. As a takeaway, we also get to understand

relativity itself better, as we provide a more formal treatment of special relativity,

which becomes a powerful tool to develop theories consistent with relativity.