1. 25.1 The Electromagnetic Spectrum

2. Light is a kind of wave A sound wave is an oscillation of air.
A water wave is an oscillation of the surface of water.
An oscillation of electricity and magnetism creates electromagnetic waves.

3. Electromagnetic Waves

4. Electromagnetic Spectrum EXAMPLE
List the following types of electromagnetic waves in order of increasing energy:
Visible light
X-rays
Microwaves
Gamma rays

5. The Electromagnetic Spectrum
Longer wavelength = lower energy
Shorter wavelength = higher energy

6. Visible Light
Different colored light has different energies.

7. Speed of Light “speed of light” = 3 x 108 m/s
The speed of electromagnetic waves is ALWAYS the same:
“speed of light” = 3 x 108 m/s

8. Speed of Light EXAMPLE
speed of light = 3 x 108 m/s
What is the frequency of a light wave with a wavelength of 340 nm (340 x 10-9 m)?

10. Electromagnetic Waves
In a similar way, the force between two electric charges is carried by an electric field.

11. Electromagnetic Waves
If you could shake the magnet up and down 100 million times per second, you would make FM radio waves at 100 million Hz (100 MHz).