Visible Light Spectrum Explained - Wavelength Range / Color Chart Diagram - Chemistry

The Organic Chemistry Tutor
26 Aug 201611:11
EducationalLearning
32 Likes 10 Comments

TLDRThis educational video delves into the visible light spectrum, explaining the sequence of colors from ROYGBIV and their corresponding wavelengths, frequencies, and energies. It clarifies misconceptions about wavelength lengths, detailing the relationship between wavelength and energy. The script also covers the visible spectrum's range, equations relating speed of light, wavelength, and frequency, and how to calculate photon energy using Planck's constant. It concludes with converting energy from joules to electron volts, providing a comprehensive guide to understanding light's properties.

Takeaways
  • 🌈 The visible light spectrum is represented by the acronym ROYGBIV, which stands for Red, Orange, Yellow, Green, Blue, Indigo, and Violet, in order of increasing energy.
  • πŸ” Infrared light is located to the left of red light and is outside the visible spectrum, while ultraviolet light is to the right of violet and also not visible to the human eye.
  • πŸ“‰ As you move from red to violet in the visible spectrum, the frequency of light increases, and so does its energy, while the wavelength decreases.
  • πŸ”΅ Blue light has a higher frequency and more energy than red light, but red light has a longer wavelength.
  • πŸ’‘ The visible light spectrum wavelengths range from approximately 400 nanometers (violet) to 700 nanometers (red).
  • πŸ€” To determine the energy, frequency, and wavelength relationships, one must understand the equations involving speed of light (c), wavelength (Ξ»), frequency (v or f), and Planck's constant.
  • βš–οΈ The speed of light in a vacuum is a constant 3 x 10^8 meters per second, but it slows down when passing through materials like glass or water due to their refractive indices.
  • πŸ“ To calculate the frequency of a photon, divide the speed of light by the wavelength in meters. Convert nanometers to meters by multiplying by 10^-9.
  • ⚑ The energy of a photon can be calculated using the equation E = h Γ— v, where h is Planck's constant (6.626 x 10^-34 joules seconds).
  • πŸ”‹ Photon energy can also be expressed in electron volts (eV), with 1 eV equal to 1.602 x 10^-19 joules. Convert joules to eV by dividing by this value.
  • πŸ“š Understanding the visible light spectrum, its associated wavelengths, and the ability to calculate frequency and energy of photons is essential for grasping fundamental concepts in physics.
Q & A
  • What is the ROYGBIV acronym and what does it represent?

    -ROYGBIV is an acronym that represents the colors of the visible light spectrum in order of increasing energy, where R stands for Red, O for Orange, Y for Yellow, G for Green, B for Blue, I for Indigo, and V for Violet.

  • What types of light are located outside the visible light spectrum, to the left of red and to the right of violet?

    -Infrared light is located to the left of red light, and ultraviolet light is located to the right of violet light. Both are outside the visible light spectrum and cannot be seen by the human eye.

  • How does the frequency of light relate to its energy and wavelength?

    -The frequency of light is directly proportional to its energy but inversely proportional to its wavelength. This means that as the frequency increases, the energy increases, and the wavelength decreases.

  • Which photon has more energy, a green photon or a yellow photon, and why?

    -A green photon has more energy than a yellow photon because, according to the ROYGBIV order, green light is to the right of yellow light, indicating a higher frequency and thus more energy.

  • What is the relationship between the frequency of a photon and its position in the visible light spectrum?

    -The frequency of a photon increases as you move from the left (red) to the right (violet) in the visible light spectrum. Therefore, a photon of violet light has a higher frequency than a photon of red light.

  • Which color light has the longest wavelength in the visible light spectrum?

    -Red light has the longest wavelength in the visible light spectrum, as it is located at the far right end of the ROYGBIV sequence.

  • What is the range of wavelengths for the visible light spectrum?

    -The visible light spectrum ranges from approximately 400 nanometers (violet) to about 700 nanometers (red).

  • How can you determine the frequency of light given its wavelength?

    -The frequency of light can be determined using the equation v = c / Ξ», where v is the frequency, c is the speed of light (approximately 3 x 10^8 meters per second), and Ξ» (lambda) is the wavelength in meters. You must convert the wavelength from nanometers to meters before calculating.

  • What is Planck's constant and how is it used to calculate the energy of a photon?

    -Planck's constant is approximately 6.626 x 10^-34 joules seconds. It is used in the equation E = hΞ½, where E is the energy of the photon, h is Planck's constant, and Ξ½ (nu) is the frequency of the photon.

  • How can you convert the energy of a photon from joules to electron volts?

    -To convert the energy of a photon from joules to electron volts, divide the energy in joules by 1.602 x 10^-19, which is the energy equivalent of one electron volt in joules.

  • What is the energy of a photon with a wavelength of 500 nanometers?

    -A photon with a wavelength of 500 nanometers has an energy of approximately 3.976 x 10^-19 joules, which is equivalent to about 2.48 electron volts.

Outlines
00:00
🌈 Understanding the Visible Light Spectrum

This paragraph introduces the visible light spectrum, explaining the sequence of colors (ROYGBIV) from red to violet and their relation to energy, frequency, and wavelength. It clarifies that red light has the longest wavelength and least energy, while violet has the shortest wavelength and most energy. The paragraph also poses questions to engage viewers in understanding these concepts, such as which photon has more energy and which has a higher frequency, and provides the correct answers based on the spectrum's arrangement.

05:00
πŸ”¬ Wavelength and Frequency Relationships

The second paragraph delves into the specific ranges of wavelengths for each color in the visible light spectrum, from violet at 400 nanometers to red at 700 nanometers. It explains how to determine the color corresponding to a given wavelength and introduces fundamental equations relating the speed of light (c), wavelength (lambda), and frequency (v or f). The paragraph also discusses how the speed of light is affected by different media and provides a step-by-step calculation to determine the frequency of light with a given wavelength.

10:02
⚑ Calculating Photon Energy and Units Conversion

The final paragraph focuses on calculating the energy of a photon using Planck's constant and the frequency of the photon. It demonstrates how to find the energy of a photon at a specific wavelength (500 nanometers) and convert that energy from joules to electron volts, a common unit in quantum physics. The summary emphasizes the importance of unit conversion and provides the formula and calculation for understanding photon energy in different units.

Mindmap
Keywords
πŸ’‘Visible Light Spectrum
The visible light spectrum refers to the range of electromagnetic waves that can be detected by the human eye. It is a subset of the larger electromagnetic spectrum and includes the colors we see in a rainbow. In the context of the video, the visible light spectrum is the focus for discussing the properties of light such as color, wavelength, frequency, and energy. The script explains that the spectrum ranges from violet light at approximately 400 nanometers to red light at about 700 nanometers.
πŸ’‘ROYGBIV
ROYGBIV is an acronym used to remember the sequence of colors in the visible light spectrum, arranged from red to violet. Each letter stands for a color: Red, Orange, Yellow, Green, Blue, Indigo, and Violet. The script uses this acronym to introduce the colors found in the visible light spectrum and to discuss their order in terms of increasing energy.
πŸ’‘Wavelength
Wavelength is the distance between two consecutive points in a wave that are in the same phase, such as from one peak to another in a light wave. The video script explains that wavelength is inversely related to frequency and energy within the visible light spectrum, with red light having the longest wavelength and violet having the shortest.
πŸ’‘Frequency
Frequency is the number of wave cycles that pass a given point in a given period of time, typically measured in hertz (Hz). The video script describes how frequency increases as we move from red to violet in the visible light spectrum, with blue light having a higher frequency than red light due to its position on the spectrum.
πŸ’‘Energy
The energy of a photon is directly related to its frequency, as described by the script. Photons with higher frequencies, such as those of blue light, have more energy than those with lower frequencies, like red light. This concept is important for understanding how different colors of light interact with matter.
πŸ’‘Infrared
Infrared is a type of electromagnetic radiation that lies just beyond the red end of the visible light spectrum. It is not visible to the human eye but can be detected by certain devices. The script mentions infrared in the context of being outside the visible light spectrum, indicating that it has a longer wavelength than red light.
πŸ’‘Ultraviolet
Ultraviolet radiation is electromagnetic radiation with a wavelength shorter than that of violet light but longer than X-rays. It is also not visible to the human eye. The script discusses ultraviolet as being beyond violet in the electromagnetic spectrum and as something we can be exposed to from the sun.
πŸ’‘Speed of Light
The speed of light in a vacuum is a fundamental constant in physics, approximately 299,792 kilometers per second. The video script uses this constant in the context of calculating the frequency of light from its wavelength, using the equation c = λν, where c is the speed of light, λ is the wavelength, and ν is the frequency.
πŸ’‘Planck's Constant
Planck's constant is a fundamental physical constant that relates the energy of a photon to its frequency. With a value of approximately 6.626 Γ— 10^-34 joule-seconds, it is used in the script to calculate the energy of a photon given its frequency, as per the equation E = hΞ½, where E is the energy, h is Planck's constant, and Ξ½ is the frequency.
πŸ’‘Electron Volt
An electron volt is a unit of energy commonly used in the fields of chemistry and physics to express the energy changes accompanying chemical or nuclear reactions. The script mentions electron volts as a unit for expressing the energy of photons, with 1 eV equal to 1.602 Γ— 10^-19 joules, and demonstrates how to convert the energy of a photon from joules to electron volts.
πŸ’‘Index of Refraction
The index of refraction is a measure of how much light slows down when it passes through a particular medium, as compared to a vacuum. The script briefly touches on this concept when explaining that the speed of light in a material is determined by the speed of light in a vacuum divided by the index of refraction of that material.
Highlights

The video focuses on the visible light spectrum, discussing colors, wavelengths, frequency, energy, and the relationships among them.

The ROYGBIV mnemonic ranks the colors of light in order of increasing energy.

Infrared and ultraviolet light are outside the visible light spectrum, with infrared to the left of red and ultraviolet beyond violet.

The frequency of light increases to the right on the spectrum, with blue light having a higher frequency and more energy than red light.

Red light has a longer wavelength, while violet has the shortest in the visible light spectrum.

The visible light spectrum ranges from 400 to 700 nanometers, with violet at the shorter end and red at the longer end.

The color corresponding to a specific wavelength can be determined by its position within the 400-700 nanometer range.

The speed of light in a vacuum is a constant, but it slows down when passing through materials like water, glass, or diamond.

The speed of light in a material is calculated by dividing the speed of light in a vacuum by the material's index of refraction.

The frequency of light can be calculated using the speed of light divided by its wavelength.

Planck's constant is used to calculate the energy of a photon by multiplying it with the photon's frequency.

The energy of a photon at 500 nanometers is approximately 3.976 x 10^-19 joules.

Energy can also be expressed in electron volts, with 1 electron volt equal to 1.602 x 10^-19 joules.

The video provides equations and examples to understand the relationship between wavelength, frequency, and energy.

The video concludes with the practical application of converting wavelength to frequency, frequency to energy, and joules to electron volts.

Transcripts
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