Key Properties and Everyday Applications of Visible Light
People always see the visible light spectrum, however, some people may be aware of it. In this article, we will get to know about the visible spectrum, wavelength, and colors.
Visible light is that section of electromagnetic waves that is perceivable to human eyes. Anything that glows or produces light has waves of visible light.
The sun, candles, light bulbs, and fire are the things that usually come in people's minds when they think of light, but visible light is produced from many sources in many different colors.
Some other sources of visible light include television and computer screens, fireworks, and glow sticks.
Visible light forms all the colors of the rainbow.
Each color has a different frequency and wavelength. When all the colors (i.e., all frequency and wavelength) come together, they form the normal "white" light.
(image will be uploaded soon)
What is the Visible Spectrum?
Visible spectrum is a field of the electromagnetic spectrum that is visible to the human eye. The wavelength of electromagnetic radiation visible to the human eye is called visible light or simply light. Wavelengths of the range of between 380 to 740 nanometers are perceivable to human eyes. Considering the frequency, this corresponds to a band frequency between 405 to 790 THz.
Here, the spectrum doesn't contain the entire colors, which can be distinguished by the human visual system.
For example, unsaturated colors like pink, or purple variations like magenta are absent because these colors can only be made from a mixture of multiple wavelengths. The colors which contain only one wavelength are called pure colors or spectral colors.
Electromagnetic radiations are transmitted in the form of waves of different wavelengths and frequencies. This broad range of wavelengths of the electromagnetic radiations is called the electromagnetic spectrum.
Electromagnetic spectrum is divided into seven regions in the increasing order of frequency and decreasing order of wavelength. These are radio waves, microwaves, infrared (IR), visible light, ultraviolet (UV), X-rays, and gamma-rays.
The visible light falls between the range of the ultraviolet and infrared regions. The frequency of visible light varies from 4 × 1014 to 8 × 1014 Hz, and the wavelength of visible light varies from 380 nanometers to 740 nanometers.
(image will be uploaded soon)
Spectral Colors
(image will be uploaded soon)
(image will be uploaded soon)
The spectral colors are also called rainbow colors. A spectral color is made up of a single fundamental wavelength on the visible portion of the electromagnetic spectrum, and it's not composed of a mixture of a number of colours. Spectrals like red, green, orange, and yellow are made up of light waves of a single frequency.
Colors which are produced by visible light of a single wavelength (monochromatic light) are called pure spectral colors. The electromagnetic spectrum is a continuous spectrum with no clear boundaries between one color and the next.
What Does Visible Light do?
The wavelength of light is strong enough to penetrate the retina of the eye and the uppermost dermis in the skin. Humans are capable of perceiving light of wavelength range between 400 nanometers (nm) and 780 nanometers (nm). In fact, there is a gradual transition of wavelengths in the visible part of the spectrum.
Moreover, the eyesight of an individual also varies differently throughout a lifetime due to the aging process of the eye. Significantly, the transparency for short wavelengths of the spectrum, like blue light, decreases with age.
The most important natural source of light for us is the sun. Artificial lights are also very important in our everyday life.
What are Visible Light Examples?
The sun produces visible light.
Incandescent light bulbs.
Neon lights.
Fluorescent tubes.
Led bulbs are some other examples of visible light that we use in our day-to-day life.
Visible light is the most important electromagnetic wave for us.
Significance of Light
It is because of light that life is possible on Earth. We do see things only because of light. It also has biological effects; it influences the sleep/wake cycle. It has been used for medicinal and cosmetic proposes for years.
Devices like lasers and IPL function with different wavelengths of lights. For example, light having a high proportion of blue light (or the corresponding wavelength) is used in light therapy devices, daylight lamps to treat "winter depression." The natural light is used to set the body clock.
Visible lights are essential because, without it, our eyes cannot process images, and we can't see anything. Apart from sight, there are also many other uses of visible lights. Visible lights are used to make lasers, treat medical surgery, electronic devices like TV, computer, mobile phones and in electric bulbs, etc.
Do You Know?
Sir Isaac Newton divided his color wheel in the following colors, which was: red, orange, yellow, green, blue, indigo, and violet. This order is also said to be "Roy G Biv", otherwise "VIBGYOR" when taken from the reverse side. In modern divisions of the colors of the spectrum, indigo is often omitted.
FAQs on What Is Visible Light? Spectrum, Colors & Importance
1. What is visible light and how does it fit within the electromagnetic spectrum?
Visible light is the portion of electromagnetic radiation that can be detected by the human eye, with wavelengths ranging from about 380 to 740 nanometers. It sits between the infrared and ultraviolet regions in the electromagnetic spectrum, making it the only segment humans can naturally perceive as colors.
2. What are the main colors in the visible spectrum, and what determines each color?
The visible spectrum contains the colors red, orange, yellow, green, blue, indigo, and violet, often remembered as VIBGYOR. Each color is determined by a unique wavelength and frequency.
- Red: longest wavelength, lowest frequency
- Violet: shortest wavelength, highest frequency
3. Why are some colors like pink and magenta absent from the visible spectrum?
Colors such as pink and magenta are not part of the visible spectrum because they are not produced by a single wavelength of light. These non-spectral colors are formed by mixing two or more different wavelengths, unlike spectral colors (pure colors) which correspond to one wavelength only.
4. What are the key properties of visible light that enable us to see objects?
Visible light has several properties that make vision possible:
- Reflection: light bounces off surfaces to enter our eyes
- Refraction: light bends when passing through materials like water or glass, clarifying images
- Dispersion: splitting of white light into its component colors, as in a rainbow
- Scattering: explains why the sky appears blue
5. What is the biological importance of visible light for humans?
Visible light is essential for vision, allowing us to see and process images. It also influences biological processes such as the sleep/wake cycle (circadian rhythm) and plays roles in medicine, for example, in light therapy. Without visible light, human life and daily functioning would be impossible.
6. How does the wavelength of visible light affect its interaction with matter?
The wavelength of visible light determines how deeply it can penetrate materials. Shorter wavelengths (blue/violet) have more energy and are scattered more easily, while longer wavelengths (red/orange) penetrate further. This affects phenomena like sky color and why sunsets appear red.
7. How do various sources produce visible light, and what are examples from daily life?
Natural sources like the Sun and stars emit visible light through nuclear reactions, while artificial sources such as bulbs, LEDs, and screens produce it by electrical excitation, heating, or chemical reactions. Examples in daily life include sunlight, electric bulbs, computer and television screens, fireworks, and glow sticks.
8. What is white light, and how is it formed from spectral colors?
White light is a combination of all the spectral colors in the visible spectrum. When light of various wavelengths (colors) are mixed in equal proportions, they combine to produce white light, as seen in sunlight or light emitted from some bulbs.
9. How does the perception of visible light change with age?
As people age, their eyes become less transparent to shorter wavelengths such as blue light. This reduces sensitivity to blue and violet colors, causing changes in color perception and possibly affecting vision clarity over time.
10. Why is visible light crucial for both technology and nature?
Visible light is vital in technology for devices like lasers, cameras, screens, and medical equipment. In nature, it drives photosynthesis and supports ecosystems. Its ability to deliver energy and information makes it fundamental for technological advances and sustaining life on Earth.
