Chapter 7 Quantum Theory and Electronic Structure of Atoms (Ch7 Chang, Ch7 Jespersen)
The Wave Nature of Light
Electromagnetic radiation (defined on next slide) can be described as light energy and/or a wave.
A wave is a vibrating disturbance by which energy is transmitted.
Waves are characterized by their length, height and by the number of waves that pass a certain point in one second.
Wavelength, λ, in meters or nanometers.
1
Frequency, ν, in or s-1, also Hz.
s
These two waves have the same amplitude;
but the top wave has longer wavelength, and
the lower wave has higher frequency.
Wavelength is the distance between identical points on successive waves.
Frequency is the number of waves that pass a point in one second.
Amplitude is the vertical distance from the midline of the wave to the peak (or trough).
AJR Ch7 Quantum Theory and Electronic Structure of Atoms.docx Slide 1
,The speed of a wave is also important, and depends on the type of wave, and the medium of travel.
Speed of a wave = wavelength x frequency
= λν
UNIT CHECK m⋅s-1 = m s-1
There are many types of waves; here we are concerned with waves that have systematic fluctuations in intensities
of electrical and magnetic components, which Maxwell in 1873 called Electromagnetic waves, of which light is an
example.
The transmission (and emission) of energy in the form of
electromagnetic waves is called Electromagnetic radiation.
The speed of electromagnetic waves (e.g. light), is a constant in a
given medium.
The speed of light, c, is approx. 3.00 x 108 m/s in a vacuum.
Often use the eqn: c = λ ν
The wavelength of electromagnetic radiation is often reported in
nanometers (nm) which is 10˗9 m.
AJR Ch7 Quantum Theory and Electronic Structure of Atoms.docx Slide 2
,The Electromagnetic Spectrum
NOTICE: Energy increases Wavelength increases Frequency increases
AJR Ch7 Quantum Theory and Electronic Structure of Atoms.docx Slide 3
, Problem: Calculate the wavelength, in meters, of radiation with a frequency of 1.18 x 1014 s–1.
What region of the electromagnetic spectrum is this?
c
λ =
ν
This is in the infrared region.
AJR Ch7 Quantum Theory and Electronic Structure of Atoms.docx Slide 4
The Wave Nature of Light
Electromagnetic radiation (defined on next slide) can be described as light energy and/or a wave.
A wave is a vibrating disturbance by which energy is transmitted.
Waves are characterized by their length, height and by the number of waves that pass a certain point in one second.
Wavelength, λ, in meters or nanometers.
1
Frequency, ν, in or s-1, also Hz.
s
These two waves have the same amplitude;
but the top wave has longer wavelength, and
the lower wave has higher frequency.
Wavelength is the distance between identical points on successive waves.
Frequency is the number of waves that pass a point in one second.
Amplitude is the vertical distance from the midline of the wave to the peak (or trough).
AJR Ch7 Quantum Theory and Electronic Structure of Atoms.docx Slide 1
,The speed of a wave is also important, and depends on the type of wave, and the medium of travel.
Speed of a wave = wavelength x frequency
= λν
UNIT CHECK m⋅s-1 = m s-1
There are many types of waves; here we are concerned with waves that have systematic fluctuations in intensities
of electrical and magnetic components, which Maxwell in 1873 called Electromagnetic waves, of which light is an
example.
The transmission (and emission) of energy in the form of
electromagnetic waves is called Electromagnetic radiation.
The speed of electromagnetic waves (e.g. light), is a constant in a
given medium.
The speed of light, c, is approx. 3.00 x 108 m/s in a vacuum.
Often use the eqn: c = λ ν
The wavelength of electromagnetic radiation is often reported in
nanometers (nm) which is 10˗9 m.
AJR Ch7 Quantum Theory and Electronic Structure of Atoms.docx Slide 2
,The Electromagnetic Spectrum
NOTICE: Energy increases Wavelength increases Frequency increases
AJR Ch7 Quantum Theory and Electronic Structure of Atoms.docx Slide 3
, Problem: Calculate the wavelength, in meters, of radiation with a frequency of 1.18 x 1014 s–1.
What region of the electromagnetic spectrum is this?
c
λ =
ν
This is in the infrared region.
AJR Ch7 Quantum Theory and Electronic Structure of Atoms.docx Slide 4
