Dispersion

Dispersion is a phenomenon in optics that occurs when the phase velocity of a wave varies depending on the frequency of the wave. Dispersive media are defined as media that have this characteristic in common. When referring to specificity, the phrase chromatic dispersion is also used. The term “dispersion” is most commonly associated with the field of optics, where it is used to describe light and other electromagnetic waves. However, dispersion in the same sense can apply to any type of wave motion, including acoustic dispersion in the case of sound and seismic waves, in gravity waves (ocean waves), and for telecommunication signals travelling along transmission lines (such as coaxial cable or optical fibre). When it comes to the physical world, dispersion results in a loss of kinetic energy due to absorption.

The dispersion of light as it passes through a prism made of glass.

The dispersion of white light is achieved by the use of a glass prism. This 5-faced solid has two triangular bases and three rectangular surfaces that are angled toward one another, giving it the appearance of a prism.

Light is transported through one of the rectangular faces of the prism, where it enters the prism and escapes through one of the other rectangular faces of the prism. Due to the fact that different colours of light move at different speeds, the refractive index varies from one colour to another. Consequently, as white light passes through the refracting surface of the prism, its components bend at various angles, causing the single beam of light to split into two distinct beams. Later, due to the refraction generated by the second rectangular surface, the distinct colours of light bend once more.

The passage of white light through a glass prism causes it to be divided into its constituent colours in this manner. The dispersion and scattering of light can be used to explain a wide range of natural phenomena that appear to be unexplained.

A Rainbow formation 

When seen in nature, water droplets are typically spherical in shape and contain water that has a refractive index that allows light to refract through them. Through the process of dispersion, sunlight (white light) strikes water droplets suspended in air, causing them to refract and spread into their constituent colours. When sunlight strikes a water droplet (at a specific angle), the light is refracted and distributed, creating a rainbow effect. In the following step, the refracted light is subjected to total internal reflection, which causes light rays to fall on the front side of the droplet and exit from the rear side.

The path of the sun’s rays through a single water droplet.

The rainbow pattern is made up of seven different colours that are arranged in a certain manner. This is due to the fact that the wavelength of red light is higher, resulting in the least amount of deviation, whereas the wavelength of violet light is lower, resulting in the greatest amount of deviation. As a result, the red light is located at the bottom of the display and the violet light is located at the top.

The colour of the sky changes depending on the time of day.

In order for sunlight to reach Earth’s atmosphere, it must first be scattered by gases and particles in the atmosphere. Because it travels in shorter, smaller waves than most other colours, blue (and violet) light disperses more widely than most other colours. This is why the sky looks blue most of the time.

Different colours of sun’s rays 

During the voyage of light from the sun to Earth’s atmosphere, the violet, indigo, blue, and green colours of the electromagnetic spectrum are scattered because air particles grow in diameter as they move closer to the earth’s surface. Yellow, the next spectral colour in terms of shortest wavelength, scatters the most near the observer’s eye, causing it to take precedence over the other spectral colours. As a result, the sun appears to be yellow in appearance.

In the winter, the colour of smoke changes.

Because the smoke from chimneys scatters the blue light the most, it takes precedence over the other spectral colours and appears as blue smoke instead of white smoke.

The application of ultramarine

An ultramarine is a fluorescent substance that absorbs ultraviolet energy from the sun and converts it into visible light, which can be seen in the form of spectrum colours such as violet, indigo, and blue. Because the sun’s rays have been diffused over the upper atmosphere, it is weak in these colours. In this way, when sunlight falls on clothes that have been soaked in ultramarine, the inadequate sunlight, due to fluorescence, contains all of the spectral colours in equal proportion once again. As a result, our brain interprets it as being white in colour.

Conclusion

Colored light is composed of a mixture of different wavelengths of light. In different media, different colours of light flow at different speeds with varied velocities.

The term “dispersion” refers to the feature of light that causes it to spread out according to its colour as it travels through an object in physics. In the case of a prism, for example, when you beam a white light into it, all of the different hues of light are bent at different angles, causing them to spread out and form a rainbow. This is possible because of the fact that different colours of light have distinct wavelengths, which explains how it works. (The wavelength of a wave is defined as the distance between its peaks.) Light interacts with the chemical structure of the prism in a variety of ways depending on the wavelength of the light being used. As a result, different wavelengths of light are twisted to varying degrees.