1. The speed of light - NOTES The speed of light, written c, is c = 3.00 x 10 8 m/s, Nothing can travel faster than light, and no object can even travel that fast

2. The speed of light - facts Light could make 7.5 trips around the earth in 1 second Light takes 8 minutes from the sun to here Light takes 4 years from Alpha Centauri, the next nearest star –The distance light travels in one year, about 10 16 meters is called a light year –An image of Alpha Centauri really shows that star 4 years ago, when the light left there

3. What is light? - NOTES Light is created by accelerating electric charges. This energy travels as an electromagnetic wave.

4. Electromagnetic waves - NOTES The Electromagnetic Spectrum: the range of light with different frequency and wavelength, shown on p 536

5. Wavelength is listed along the bottom, increasing from left to right Frequency is listed along the top, decreasing from left to right

6. Reference Table Time Another view…

7. Visible light - NOTES The wavelength of visible light, then, ranges from about 4 x 10 -7 m to 8 x 10 -7 m, or 400 nm to 800 nm

8. Practice 1)What is the wavelength range for X- rays? 2)What is the frequency range for X-rays? 3) What is the maximum frequency of Radio Waves?

9. Practice 5) What is the frequency range of Ultraviolet light? 6) Why is it called Ultraviolet? 7) What is the frequency range of Infrared light? 8) Why is it called Infrared?

10. Homework: P 549 #25, 27, 29, 30, 52, 59