What is Light Spectrum? | Definition, Types, Formula & Examples

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Frequency and Wavelength

One of the characteristics of light is that it acts like a wave. Accordingly, light can be determined by its wavelength and frequency. Frequency is the speed at which a wave oscillates or rises and falls. Wavelength is the distance between two wave crests. Frequency and wavelength are inversely proportional, that is, low frequency waves have longer wavelengths and vice versa.

We can only see light in a certain range of wavelengths and frequencies. This range is called the visible spectrum. The frequency range of the visible spectrum is 405 terahertz to 790 terahertz.

The Electromagnetic Spectrum

The electromagnetic spectrum consists of many types of light waves, some of which we cannot see. Some types of waves that cannot be seen are radio waves, microwaves, infrared rays, and X-rays. These waves have all sorts of uses in science and technology.

In the visible light spectrum, the color of light depends on the frequency. The visible spectrum is always the same for a rainbow or light separated from a prism. The color order is red, orange, yellow, green, blue, indigo, and violet. A fun way to remember this is to use the first letter of each color to spell out the name ROY G. BIV.

Colors of light

What we see when we see an object is reflected light. When light hits an object, some wavelengths are absorbed by the object and some are reflected. Light of different wavelengths looks like different colors to us. When we see an object of a certain color, it means that light of that color’s wavelength is reflected from the object.

For example, when you see a red shirt, that shirt absorbs all light colors except red. The frequency of light that we see as red is reflected and we see this shirt as red.

Black and white are slightly different from other colors. White is the sum of all colors, so when we see white, the object reflects all colors of light equally. Black is the opposite. When we see a black object, it means that almost all colors of light have been absorbed.

Additive colors

Light from the three additive primary colors can be combined to create any other color. These three colors are red, blue and green. This fact is always used in technologies such as computer monitors and televisions. By combining only the three main types of light in different ways, any color can be produced.

Subtractive colors

If you have white light and want to subtract colors to get another color, you would use primary subtraction colors to filter or remove the light of certain colors. The minus primary colors are cyan, magenta, and yellow.