Chapter 32: Electromagnetic (EM) Waves

Electromagnetic waves (also called electromagnetic radiation) are waves that obey Maxwell's equations.  One of the consequences of Maxwell's equations is that there are electromagnetic waves that propagate at 3 x 10⁸ m/s in a vacuum.  This is precisely the speed of light in a vacuum!  Therefore, all light—visible light, ultraviolet radiation, radio waves, microwaves, x-rays, gamma rays, and infrared radiation—is an electromagnetic wave.  The difference between these waves is simply in the frequency (f ) or wavelength (λ).  Since the frequency times the wavelength (f λ) is equal to the speed of propagation (which for light in a vacuum must be 3 x 10⁸ m/s), if you know the frequency, you know the wavelength.  This chapter examines propagating electric and magnetic fields and links them to the observable properties of light.

Table of Contents

Illustrations

• Illustration 32.1: Creation of Electromagnetic Waves.
• Illustration 32.2: Wave Crests.
• Illustration 32.3: Electromagnetic Plane Waves.
• Illustration 32.4: Electromagnetic Waves, E x B.

Explorations

• Exploration 32.1: Representation of Plane Waves.
• Exploration 32.2: Plane Waves and the Electric Field Equation.

Problems

• Problem 32.1: Electric field vs. magnetic field.
• Problem 32.2: Animation A is green light, what is Animation B?
• Problem 32.3: Which animation represents which color?
• Problem 32.4: Characterize the electromagnetic wave.
• Problem 32.5: Characterize the electromagnetic wave.
• Problem 32.6: Field produced by oscillating charge.