Everything Science Grade 10

11.2 CHAPTER 11. ELECTROMAGNETIC RADIATION

We useEto denote electric fields andBto denote magnetic fields.

These concepts will be covered in more detail in Grade 11.

These mutually regenerating fields, most commonly described as self-propagating, travel
through empty space at a constant speed of approximately 3 × 108 m·s−^1 , represented
byc. We will use 3 × 108 m·s−^1 for all of our calculations in this book. Although an
electromagnetic wave can travel through empty space, it can also travel through a medium
(such as water and air). When an electromagnetic wave travels through a medium, it travels
slower than it would through empty space (vacuum).

x

B

E

Figure 11.2: A diagram showing the mutually regenerating electric field (red (solid) line)
and magnetic field (blue (dashed) line).

Since an EM radiation is a wave, the following equation still applies:

v=f·λ

Except that we can replacevwithc:

c=f·λ

188 Physics: Waves, Sound and Light