UNIT OVERVIEW

Visible light—the colours you see every day—is just a tiny part of a much larger family of energy called electromagnetic radiation. From the radio waves that carry your favourite music to the X-rays that let doctors see inside your body, electromagnetic radiation is everywhere.

In the previous section, you explored longitudinal waves and how sound travels through matter. Now you will meet a different kind of wave—one that does not need any medium at all. It can travel through empty space at the fastest speed in the universe.

In this unit, you will learn:

• The dual nature of electromagnetic radiation—how it behaves as both a wave and a particle
• What electromagnetic radiation is and how it differs from mechanical waves
• The complete electromagnetic spectrum from radio waves to gamma rays
• How to calculate the energy of a photon using $E = hf$ and $E = \frac{hc}{\lambda}$
• The relationship between frequency, wavelength, and energy
• Real-world applications of each region of the EM spectrum

Everyday examples of electromagnetic radiation: