What is the Difference Between Visible Light Infrared and Ultraviolet

The main difference between visible light infrared and ultraviolet is that the wavelength of visible light is 400-700 nm, and the wavelength of infrared is 700 nm -1 mm, whereas the wavelength of ultraviolet is 10-400 nm.

Visible light, infrared, and ultraviolet are three portions of the electromagnetic spectrum. Generally, visible light contains the portion that is visible to the human eye while the other two portions are invisible to the human eye. In addition, infrared has longer wavelengths than visible light while ultraviolet has shorter wavelengths than visible light.

Key Areas Covered

1. What is Visible Light
   • Definition, Features, Importance
2. What is Infrared
   • Definition, Features, Importance
3. What is Ultraviolet
   • Definition, Features, Importance
4. Similarities Between Visible Light Infrared and Ultraviolet
   • Outline of Common Features
5. Difference Between Visible Light Infrared and Ultraviolet
   • Comparison of Key Differences

Key Terms

Infrared, Ultraviolet, Visible Light

What is Visible Light

Visible light is the portion of the electromagnetic spectrum that is visible to the human eye. This portion is also known as the visible spectrum or simply as light. Significantly, the human eye only responds to the wavelength range from 380 nm to 750 nm. However, in optimal conditions, the human eye can respond from 310 nm (ultraviolet) to 1100 nm (near infrared), which is known as the optical spectrum.

Figure 1: Visible Spectrum

Furthermore, there are two types of color types in the visible spectrum: pure spectral colors and unsaturated colors. The pure spectral colors include red, orange, yellow, green, cyan, blue, and violet. Colors like pink, purple, and magenta are unsaturated colors, and they contain a mix of multiple wavelengths. But pure spectral colors contain single wavelengths.

What is Infrared

Infrared is the portion of the electromagnetic spectrum with longer wavelengths than the visible spectrum. Usually, it extends from the nominal red edge of the visible spectrum at 700 nm. It ends up in the microwave region at the wavelengths of 1 mm. Almost all black-body radiation from objects near room temperature is at infrared wavelengths. As it is electromagnetic radiation, it passes energy and momentum.

Figure 2: Infrared Images

Infrared radiation is important in industrial, scientific, military, commercial, and medical applications. Night-vision devices using active near-infrared illumination allow the observation of people or animals without the observer being detected. Infrared thermal-imaging cameras are used to detect heat loss in insulated systems, observe changing blood flow in the skin, and detect the overheating of electrical components. Furthermore, infrared astronomy uses sensor-equipped telescopes to penetrate dusty regions of space such as molecular clouds, detect objects such as planets, and view highly red-shifted objects from the early days of the universe.

What is Ultraviolet

Ultraviolet is the portion of the electromagnetic spectrum with shorter wavelengths than the visible spectrum. Generally, it starts from the violet edge of the visible spectrum at 400 nm. It ends up in the X-ray region at wavelengths of 10 nm. Although its wavelengths are shorter than the visible spectrum, they are longer than X-ray radiation. UV radiation is present in sunlight and constitutes about 10% of the total electromagnetic radiation output from the Sun.

Figure 3: Ultraviolet Lamp

Moreover, long-wavelength ultraviolet is not ionizing radiation because its photons lack the energy to ionize atoms. It can just cause chemical reactions and causes many substances to glow or fluoresce. In contrast, shorter wavelengths of ultraviolet radiation can cause DNA damage and these wavelengths are important in surface sterilizations. In humans, suntan and sunburn are familiar effects of exposure of the skin to UV light, along with an increased risk of skin cancer.

Similarities Between Visible Light Infrared and Ultraviolet

• Visible light, infrared, and ultraviolet are three portions of the electromagnetic spectrum.
• Moreover, they have different applications depending on their wavelengths.

Difference Between Visible Light Infrared and Ultraviolet Light

Definition

Visible light refers to the portion of the electromagnetic spectrum that is visible to the human eye, infrared refers to electromagnetic radiation (EMR) with wavelengths longer than those of visible light, while ultraviolet refers to a form of electromagnetic radiation with a wavelength from 10 nm.

Wavelengths

Visible light has wavelengths of 400-700 nm; infrared has wavelengths of 700 nm -1 mm while ultraviolet has wavelengths of 10-400 nm.

Frequency

The frequency range of visible light is 430 THz – 750 THz and the frequency range of infrared is 300 GHz – 430 THz while the frequency range of ultraviolet is 750 THz – 30 PHz.

Photon Energy

The photon energy range of visible light is 3.3 eV – 1.7 eV and the photon energy range of infrared is 1.7 eV – 1.24 meV while the photon energy range of ultraviolet is 124 eV – 3.3 eV.

Applications

Visible light has colors while infrared is important in night vision devices and ultraviolet can cause DNA damage.

Conclusion

Visible light is the portion of the electromagnetic spectrum visible to the human eye. Generally, it has two types of colors: pure spectral colors and unsaturated colors depending on the wavelengths. However, infrared contains wavelengths longer than the visible spectrum. Generally, infrared is important in night vision. On the other hand, ultraviolet radiation has shorter wavelengths than the visible spectrum and is important in DNA damage. Therefore, the main difference between visible light infrared and ultraviolet is their wavelengths.

References:

1. Center for Science Education. Visible Light | Center for Science Education. (n.d.). Retrieved September 12, 2022.
2. (n.d.). Infrared waves. NASA. Retrieved September 12, 2022.
3. (n.d.). Ultraviolet waves. NASA. Retrieved September 12, 2022.

Image Courtesy:

1. “Linear visible spectrum” By Gringer – Own Work (Public Domain) via Commons Wikimedia
2. “Ir girl” By Masgatotkaca – Own Work (CC BY-SA 3.0) via Commons Wikimedia
3. “UV-handlamp hg” By Hannes Grobe – Own Work (CC BY-SA 3.0) via Commons Wikimedia