1. Light is an electromagnetic wave. Visible light is only a small section of the electromagnetic spectrum. The electromagnetic spectrum stretches from radio waves (low frequency, long wavelength) to gamma rays (high frequency, short wavelength)

2. Electromagnetic Radiation does not need a medium to propagate! Speed of light in vacuum, c = 3.0 x 10 8 m/s

3. Electromagnetic Radiation does not need a medium to propagate! Speed of light in vacuum, c = 3.0 x 10 8 m/s Light slows down when it passes through matter

4. Electromagnetic Radiation does not need a medium to propagate! Speed of light in vacuum, c = 3.0 x 10 8 m/s Light slows down when it passes through matter Dense materials tend to slow light down more

5. Electromagnetic Radiation does not need a medium to propagate! Speed of light in vacuum, c = 3.0 x 10 8 m/s Light slows down when it passes through matter Dense materials tend to slow light down more All electromagnetic waves obey the wave equation: v = fλ

6. Use v = f λ to complete the following table In each case, use c (3.0 x 10 8 m/s) as the velocity Type of waveTypical frequency (Hz) Corresponding wavelength (m) AM radio (LW)1024 FM radio Microwave 0.03 Infra-red2 x 10 -6 visible600 x 10 -9 Ultraviolet200 x 10 -9 X-ray & gamma2.0 x 10 18

7. Use v = f λ to complete the following table In each case, use c (3.0 x 10 8 m/s) as the velocity Type of waveTypical frequency (Hz) Corresponding wavelength (m) AM radio (LW)1024 FM radio89.5 x 10 6 3.35 Microwave 0.03 Infra-red2 x 10 -6 visible600 x 10 -9 Ultraviolet200 x 10 -9 X-ray & gamma2.0 x 10 18

8. Use v = f λ to complete the following table In each case, use c (3.0 x 10 8 m/s) as the velocity Type of waveTypical frequency (Hz) Corresponding wavelength (m) AM radio (LW)293 x 10 6 1024 FM radio89.5 x 10 6 3.35 Microwave10.0 x 10 9 0.03 Infra-red150 x 10 12 2 x 10 -6 visible500 x 10 12 600 x 10 -9 Ultraviolet1.5 x 10 15 200 x 10 -9 X-ray & gamma2.0 x 10 18 150 x 10 -12

9. When a wave passes from one medium to another The frequency stays the same. The speed of the wave may change. If so, the wavelength will change also. The wave will ALWAYS obey v = fλ The path of the wave may be bent…..