1. Chapter 6: Electromagnetic Radiation
wavelength
Visible light
Ultraviolet radiation
Amplitude
Node

2. Figure 7.1

4. Short wavelength -->
high frequency
high energy
Long wavelength -->
small frequency
low energy

6. Which has the longest wavelength?
Infrared
Ultraviolet
X-rays
Radio waves

7. Rank the following in order of increasing frequency: microwaves radiowaves X-rays blue light red light UV light IR light

8. Long wavelength --> small frequency
Waves have a frequency
Use the Greek letter “nu”, , for frequency, and units are “cycles per sec”
All radiation:  •  = c
c = velocity of light = 3.00 x 108 m/sec
Long wavelength --> small frequency
Short wavelength --> high frequency

9. What is the wavelength of WONY?
What is the wavelength of cell phone radiation? Frequency = 850 MHz
What is the wavelength of a microwave oven? Frequency = 2.45 GHz

10. Quantization of Energy
Light acts as if it consists of particles called PHOTONS, with discrete energy.
Energy of radiation is proportional to frequency
E = h • 
h = Planck’s constant = x J•s

11. E = h • 
Relationships:

12. Short wavelength light has:
High frequency and low energy
High frequency and high energy
Low frequency and low energy
Low frequency and high energy

13. Rank the following in order of increasing photon energy: microwaves radiowaves X-rays blue light red light UV light IR light

14. E = h • n
What is the energy of a WONY photon?

15. Energy of Radiation
What is the frequency of UV light with a wavelength of 230 nm?
What is the energy of 1 photon of UV light with wavelength = 230 nm?

16. What is the energy of a photon of 525 nm light?
3.79 x J
4.83 x J
3.67 x 1020 J
8.43 x 1023 J

17. Can this light break C-C bonds with an energy of 346 kJ/mol?
What is the energy of a mole of 230 nm photons?
Can this light break C-C bonds with an energy of 346 kJ/mol?

18. Does 1200 nm light have enough energy to break C-C bonds?

19. Where does light come from?
Excited solids emit a continuous spectrum of light
Excited gas-phase atoms emit only specific wavelengths of light (“lines”)

20. Light emitted by solids

21. Light emitted by hydrogen gas