radiant energy particles or waves of energy emitted electromagnetic radiation – energy released...
TRANSCRIPT
particles or waves of energy emitted Electromagnetic radiation – energy released from
all objects
Nuclear radiation – energy released when a nucleus of an atom changes
Radiation
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
Types of Electromagnetic Radiation
Ionizinghigh energy radiation
that produces ions(alpha, beta, gamma)
Non-ionizing radiationlow energy radiation
that doesn’t produce ions
Electromagnetic radiation moves in waves
Waves can be described in terms of four characteristics
•Amplitude
•Wavelength
•Frequency
•speed
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-1Speed is the speed of light: 3.00 X 108 m/s c
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 1014 1/sec?
(look in book for color)
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 = 7.26 X 1014 1/s
413 X 10-9m E= h
E=(6.6262 X 10-34 Js)(7.26 X 10141/s)
= 4.81 X 10-19J
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
Nuclear binding energy
E=mc2
Mass is converted to energyMass proton=1.0078 amuMass of neutron=1.0087 amu1J=1 kg m2/sec2
1 amu=1.66 x 10-27 kg