Introductory Electrical Engineering With Math Explained in Accessible Language

3Atom: Quarks, Protons, and Electrons

3.1 Introduction

In this chapter, we will make a brief introduction about the physics behind electricity and electromagnetism, starting at the atomic level.

3.2 Atoms and Quarks

The word atom comes from ancient Greek word meaning “indivisible,” because it was believed at the time that the atom was the smallest part of matter and could not be divided.

At the atomic level, atoms are composed of protons, neutrons, and electrons.

Today we know that these elements are composed of more elementary elements called quarks, and known to exist in six variations called flavors: top, bottom, charm, strange, up, and down.

As far as physicists know today, quarks are themselves elements that cannot be divided. Every time you try to divide them, a new quark is created.

Protons for example, are composed of two up quarks and one down quark, and neutrons are composed of two down quarks and one up quark (Figure 3.1).

Protons have a positive electric charge and neutrons have no electric charge.

Electric charge is normally represented, in physics, by the letter q or e.

In terms of reference charge, a proton is said to have an electric charge equal to 1. This charge, generally referred as e⁺, is equal to 1.602176634 × 10⁻¹⁹C.¹

Figure 3.1 A proton and its quarks.

3.3 Electrons

Electrons are stable subatomic particles with a negative charge that can ...