I. Waves & Particles
Ch. 4 - Electrons in Atoms Light, Waves & Particles
C. Johannesson
EM Radiation Electromagnetic Radiation transverse waves produced by the motion of electrically charged particles does not require a medium Photons tiny, particle-like bundles of radiation
absorbed and released by electrons
Transverse Waves
crest
A
origin trough
C. Johannesson
Waves Wavelength () - length of one complete wave Frequency () - # of waves that pass a point during a certain time period hertz (Hz) = 1/s Amplitude (A) - distance from the origin to the trough or crest C. Johannesson
Types of Electromagnetic Radiation H I G H
L O W E N E R G Y
R O Y
red
orange
G.
yellow
green
C. Johannesson
B
blue
I
indigo
V
violet
E N E R G Y
Types of EM Radiation Radiowaves lowest energy EM radiation
Types of EM Radiation Radiowaves FM - frequency modulation AM - amplitude modulation
Microwaves
penetrate food and vibrate water & fat molecules to
produce thermal energy
Types of EM Radiation Infrared Radiation (IR) slightly lower energy than visible light can raise the thermal energy of objects thermogram - image made by detecting IR radiation
Types of EM Radiation Visible Light small part of the spectrum we can see ROY G. BIV - colors in order of increasing energy
R O Y G.B V I redorangeyellowgreenblueindigoviolet
C. Types of EM Radiation Ultraviolet Radiation (UV) slightly higher energy than visible light Types: UVA - tanning, wrinkles UVB - sunburn, cancer UVC - most harmful, sterilization
Types of EM Radiation Ultraviolet Radiation (UV) Ozone layer depletion = UV exposure!
Types of EM Radiation
X rays higher energy than UV can penetrate soft tissue, but not bones
Types of EM Radiation Gamma rays highest energy EM radiation emitted by radioactive atoms used to kill cancerous cells
Radiation
EM Spectrum H I G H
L O W E N E R G Y
E N E R G Y C. Johannesson
Quantum Theory Planck (1900) Observed - emission of light from hot objects Concluded - energy is emitted in small, specific amounts (quanta) Quantum - minimum amount of energy change C. Johannesson
Quantum Theory Planck (1900)
vs. Classical Theory
Quantum Theory C. Johannesson
Quantum Theory Einstein (1905) Observed - photoelectric effect
C. Johannesson
Quantum Theory Einstein (1905) Concluded - light has properties of both waves and particles “wave-particle duality”
Photon - particle of light that carries a quantum of energy
C. Johannesson
C. Johannesson
EM Radiation Electromagnetic Radiation transverse waves produced by the motion of electrically charged particles does not require a medium Photons tiny, particle-like bundles of radiation
absorbed and released by electrons
Transverse Waves
crest
A
origin trough
C. Johannesson
Waves Wavelength () - length of one complete wave Frequency () - # of waves that pass a point during a certain time period hertz (Hz) = 1/s Amplitude (A) - distance from the origin to the trough or crest C. Johannesson
Types of Electromagnetic Radiation H I G H
L O W E N E R G Y
R O Y
red
orange
G.
yellow
green
C. Johannesson
B
blue
I
indigo
V
violet
E N E R G Y
Types of EM Radiation Radiowaves lowest energy EM radiation
Types of EM Radiation Radiowaves FM - frequency modulation AM - amplitude modulation
Microwaves
penetrate food and vibrate water & fat molecules to
produce thermal energy
Types of EM Radiation Infrared Radiation (IR) slightly lower energy than visible light can raise the thermal energy of objects thermogram - image made by detecting IR radiation
Types of EM Radiation Visible Light small part of the spectrum we can see ROY G. BIV - colors in order of increasing energy
R O Y G.B V I redorangeyellowgreenblueindigoviolet
C. Types of EM Radiation Ultraviolet Radiation (UV) slightly higher energy than visible light Types: UVA - tanning, wrinkles UVB - sunburn, cancer UVC - most harmful, sterilization
Types of EM Radiation Ultraviolet Radiation (UV) Ozone layer depletion = UV exposure!
Types of EM Radiation
X rays higher energy than UV can penetrate soft tissue, but not bones
Types of EM Radiation Gamma rays highest energy EM radiation emitted by radioactive atoms used to kill cancerous cells
Radiation
EM Spectrum H I G H
L O W E N E R G Y
E N E R G Y C. Johannesson
Quantum Theory Planck (1900) Observed - emission of light from hot objects Concluded - energy is emitted in small, specific amounts (quanta) Quantum - minimum amount of energy change C. Johannesson
Quantum Theory Planck (1900)
vs. Classical Theory
Quantum Theory C. Johannesson
Quantum Theory Einstein (1905) Observed - photoelectric effect
C. Johannesson
Quantum Theory Einstein (1905) Concluded - light has properties of both waves and particles “wave-particle duality”
Photon - particle of light that carries a quantum of energy
C. Johannesson
