1. Radiant Energy

2. particles or waves of energy emitted
Radiation
Electromagnetic radiation – energy released from all objects
Nuclear radiation – energy released when a nucleus of an atom changes

3. Electromagnetic Radiation
Energy emitted from all atoms when electrons move to different energy levels in an atom
Energy is not matter it is a wave

4. Types of Electromagnetic Radiation
Ionizing
high energy radiation that produces ions
(alpha, beta, gamma)
Non-ionizing radiation
low energy radiation that doesn’t produce ions

6. Visible Spectrum

7. Electromagnetic radiation moves in waves
Waves can be described in terms of four characteristics
Amplitude
Wavelength
Frequency
speed

8. Wavelength is distance between crests: 
measured in m, cm, mm, m, nm, etc.
Amplitude is the height of wave: Intensity of light depends on amplitude
measured in m, cm, mm, m, nm, etc.
Frequency is how fast the wave oscillates up and down: 
measured in cycles/sec. Also called a Hertz (Hz): 1/sec or sec-1
Speed is the speed of light: 3.00 X 108 m/s c

10. Calculate
Green light has a wavelength of 570 nm. What is it’s frequency?
What is the color of light that has a frequency of 4.7 x /sec?
(look in book for color)

11. Energy, frequency and wavelength are related
E= h
h= Planck’s constant
X 10-34Js

12. Calculate
A certain violet light has a wavelength of 413nm. What is the frequency of the light? What is the energy of the light?
= c/ = c/ Convert nm to m
 = 3.00X 108m/s = X /s
413 X 10-9m
E= h
E=( X Js)(7.26 X 10141/s)
= 4.81 X 10-19J

13. Light Is a form of electromagnetic radiation Has dual properties
Behaves like a wave. Moves through space in waves
Behaves like a stream of particles called photons
Light is quantized – has a specific energy

14. Wave nature of light
Oscillating electromagnetic fields

16. Nuclear binding energy
E=mc2
Mass is converted to energy
Mass proton= amu
Mass of neutron= amu
1J=1 kg m2/sec2
1 amu=1.66 x kg

17. Electromagnetic radiation has energy