1. The Wave Nature of Light Section 6.1

2. Objectives Study light (radiant energy or electromagnetic radiation) as having wavelike properties. Identify the characteristics of wavelength, frequency, and speed

3. Key Terms Electromagnetic radiation Wavelength Frequency Speed

4. Why Study Light? Our understanding of the electronic structure of atoms came from the analysis of light either emitted or absorbed

5. Visible Light Light we can see with our eyes An example of electromagnetic radiation

6. Electromagnetic Radiation Carries energy through space a.k.a radiant energy Many types of ER Visible light Radio waves Infrared radiation X rays

7. The different forms of ER share certain fundamental characteristics They all move through a vacuum as the speed of light: 3.00 x 10 8 m/s Radio AND X rays??

8. Wavelike Characteristics All ER types also behave like water waves Up and down motion Pattern of peaks and troughs repeated at regular intervals

9. Wavelength, Shortest distance between equivalent points on a continuous wave Between 2 adjacent peaks or troughs Measure in meters or nm

11. Frequency, Number of complete wavelengths or cycles that pass a given point per second. Measured in Hz (Hertz)

12. Amplitude Wave’s height from the origin to a peak, or from the origin to a trough Relates to the intensity of the radiation

13. Characteristics of Waves

14. What makes water waves travel at various speeds?

15. ER versus Water Waves ER move at the same speed Wavelength and frequency are always related

16. Why Your Radio Won’t Take an X ray ER types have different properties as a result of their varying wavelengths, expressed in units of length

17. Electromagnetic Spectrum

18. A VERY Large Spectrum Gamma rays = Radio waves =

20. Don’t Forget… ROY G BIV Order of colors (L  S) on the visible spectrum

21. Practice Problem The yellow light given off by a sodium vapor lamp used for public lighting has a wavelength of 589 nm. What is the frequency of this radiation?

22. Solution