1. ASTR 1101-001 Spring 2008 Joel E. Tohline, Alumni Professor 247 Nicholson Hall [Slides from Lecture19]

2. Chapter 5: Nature of Light Light is generated when charged particles undergo an acceleration Atoms are composed of charged particles (protons and electrons) Hence, light can be generated by individual atoms or by large collections of atoms (all normal matter with which you are familiar) Atoms can also absorb (destroy) light, with the result that charged particles associated with the atoms are accelerated

3. Chapter 5: Nature of Light Light is generated when charged particles undergo an acceleration Atoms are composed of charged particles (protons and electrons) Hence, light can be generated by individual atoms or by large collections of atoms (all normal matter with which you are familiar) Atoms can also absorb (destroy) light, with the result that charged particles associated with the atoms are accelerated

4. Chapter 5: Nature of Light Light is generated when charged particles undergo an acceleration Atoms are composed of charged particles (protons and electrons) Hence, light can be generated by individual atoms or by large collections of atoms (all normal matter with which you are familiar) Atoms can also absorb (destroy) light, with the result that charged particles associated with the atoms are accelerated

6. Chapter 5: Nature of Light Light is generated when charged particles undergo an acceleration Atoms are composed of charged particles (protons and electrons) Hence, light can be generated by individual atoms or by large collections of atoms (all normal matter with which you are familiar) Atoms can also absorb (destroy) light, with the result that charged particles associated with the atoms are accelerated

7. Chapter 5: Nature of Light Light is generated when charged particles undergo an acceleration Atoms are composed of charged particles (protons and electrons) Hence, light can be generated by individual atoms or by large collections of atoms (all normal matter with which you are familiar) Atoms can also absorb (destroy) light, with the result that charged particles associated with the atoms are accelerated

8. Chapter 5: Nature of Light Speed of Light –Finite –How is the speed measured? Colors of (visible) Light –Rainbow –Concept of spectrum (intensity vs. color) –Color identifies wavelength (and frequency) Entire electromagnetic spectrum

9. Chapter 5: Nature of Light Speed of Light –Finite –How is the speed measured? Colors of (visible) Light –Rainbow –Concept of spectrum (intensity vs. color) –Color identifies wavelength (and frequency) Entire electromagnetic spectrum

11. Chapter 5: Nature of Light Speed of Light –Finite –How is the speed measured? Colors of (visible) Light –Rainbow –Color identifies wavelength (and frequency) –Concept of spectrum ( intensity vs. wavelength ) Entire electromagnetic spectrum

13. Wavelength and Frequency Wavelength = Frequency = c = speed of light = c

14. Chapter 5: Nature of Light Speed of Light –Finite –How is the speed measured? Colors of (visible) Light –Rainbow –Color identifies wavelength (and frequency) –Concept of spectrum ( intensity vs. wavelength ) Entire electromagnetic spectrum

17. Chapter 5: Nature of Light Speed of Light –Finite –How is the speed measured? Colors of (visible) Light –Rainbow –Color identifies wavelength (and frequency) –Concept of spectrum ( intensity vs. wavelength ) Entire electromagnetic spectrum