Uploaded August 2025 | Updated September 2026, 2 weeks ago
The Electromagnetic Spectrum
Dr. DeBacco
Wavelength (λ )
To understand the electronic structure of atoms, one must understand the nature of electromagnetic radiation.
The distance between corresponding points on adjacent waves is the wavelength (λ).
Frequency
The number of waves passing a given point per unit of time is the frequency (v).
For waves traveling at the same velocity, the longer the wavelength, the smaller the frequency.
Photon Energy
Photon energy- the energy carried by a single photon, the basic unit of light or other forms of electromagnetic radiation.
Photon energy depends entirely on the frequency or wavelength of the light.
Speed of Light
The speed of light in a vacuum is exactly…
299,792,458 meters per second
OR
670,616,629 miles per hour.
It’s usually rounded to 300,000,000 m/s for easier calculations.
Scientists use the symbol c to represent it in equations
Electromagnetic Radiation
All electromagnetic radiation travels at the same velocity: the speed of light (c) = 3.00 x 108 m/s.
Colors (Visible Light/Spectrum)
ROY G BIV
R – Red
O – Orange
Y – Yellow
G – Green
B – Blue
I – Indigo
V – Violet
Order is important
These colors are arranged by wavelength, from longest to shortest:
Red has the longest wavelength (~700 nm)
Violet has the shortest (~380 nm)
White Light
White light is what we perceive when all the colors of the visible spectrum red, orange, yellow, green, blue, indigo, and violet are blended together in equal intensity.
It contains all wavelengths of visible light.
When passed through a prism, white light splits into a rainbow of colors a phenomenon called dispersion.
Common sources include sunlight, incandescent bulbs, and white LEDs.
Combining of Colors
Additive Principle
The additive principle of color mixing explains how combining different colors of light — not pigments — creates new colors. It’s the foundation of how screens, stage lighting, and digital displays work.
The primary colors of light are Red, Green, and Blue (RGB).
When these lights overlap, they add their wavelengths together, producing new colors:
Red + Green = Yellow
Green + Blue = Cyan
Blue + Red = Magenta
Red + Green + Blue = White
The Color Black
Black is a fascinating color or more precisely, a perception that can mean different things depending on whether you're talking about light or pigment.
Black is a color made by combining many pigments that absorb most wavelengths of light.
In the subtractive color model (used in paints and inks), mixing all primary colors (cyan, magenta, yellow) can produce black — though often a separate black pigment is used for depth and richness.
Our eyes see black when no light is reflected from an object.
Link to Lecture Slides: drive.google.com/file/d/1F9ITgYOatpJJ8SzcEx-L93_5PQV4NZwv/view?usp=drive_link
*Due to the description character limit the full work cited for "The Electromagnetic Spectrum" can be viewed at... docs.google.com/document/d/1fGy7zX5DyOtZa5x99FPayH3aXZkcJv1R/edit?usp=drive_link&ouid=104237452697237972847&rtpof=true&sd=true
The Electromagnetic Spectrum
Dr. DeBacco
Wavelength (λ )
To understand the electronic structure of atoms, one must understand the nature of electromagnetic radiation.
The distance between corresponding points on adjacent waves is the wavelength (λ).
Frequency
The number of waves passing a given point per unit of time is the frequency (v).
For waves traveling at the same velocity, the longer the wavelength, the smaller the frequency.
Photon Energy
Photon energy- the energy carried by a single photon, the basic unit of light or other forms of electromagnetic radiation.
Photon energy depends entirely on the frequency or wavelength of the light.
Speed of Light
The speed of light in a vacuum is exactly…
299,792,458 meters per second
OR
670,616,629 miles per hour.
It’s usually rounded to 300,000,000 m/s for easier calculations.
Scientists use the symbol c to represent it in equations
Electromagnetic Radiation
All electromagnetic radiation travels at the same velocity: the speed of light (c) = 3.00 x 108 m/s.
Colors (Visible Light/Spectrum)
ROY G BIV
R – Red
O – Orange
Y – Yellow
G – Green
B – Blue
I – Indigo
V – Violet
Order is important
These colors are arranged by wavelength, from longest to shortest:
Red has the longest wavelength (~700 nm)
Violet has the shortest (~380 nm)
White Light
White light is what we perceive when all the colors of the visible spectrum red, orange, yellow, green, blue, indigo, and violet are blended together in equal intensity.
It contains all wavelengths of visible light.
When passed through a prism, white light splits into a rainbow of colors a phenomenon called dispersion.
Common sources include sunlight, incandescent bulbs, and white LEDs.
Combining of Colors
Additive Principle
The additive principle of color mixing explains how combining different colors of light — not pigments — creates new colors. It’s the foundation of how screens, stage lighting, and digital displays work.
The primary colors of light are Red, Green, and Blue (RGB).
When these lights overlap, they add their wavelengths together, producing new colors:
Red + Green = Yellow
Green + Blue = Cyan
Blue + Red = Magenta
Red + Green + Blue = White
The Color Black
Black is a fascinating color or more precisely, a perception that can mean different things depending on whether you're talking about light or pigment.
Black is a color made by combining many pigments that absorb most wavelengths of light.
In the subtractive color model (used in paints and inks), mixing all primary colors (cyan, magenta, yellow) can produce black — though often a separate black pigment is used for depth and richness.
Our eyes see black when no light is reflected from an object.
Link to Lecture Slides: drive.google.com/file/d/1F9ITgYOatpJJ8SzcEx-L93_5PQV4NZwv/view?usp=drive_link
*Due to the description character limit the full work cited for "The Electromagnetic Spectrum" can be viewed at... docs.google.com/document/d/1fGy7zX5DyOtZa5x99FPayH3aXZkcJv1R/edit?usp=drive_link&ouid=104237452697237972847&rtpof=true&sd=true
