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Last updated date: 01st Mar 2024
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Overview of Prism

A prism is an object which is solid and with various characteristics like it has identical ends and flat faces and it has the same cross-section the entire way through. The shape created by cutting an object directly across is called a cross-section. This object's cross-section is a triangle. It is a triangular prism because it has the same cross-section along its entire length. A prism separates light in its many colours. Let’s discuss prism more, let us know what a prism does and how to use it. So let’s dive in!

Different Shapes of Prism

  • A prism is a great tool for graphically illustrating that white light is made up of seven different colours. Each of a prism's parallel ends is referred to as a base.

  • A prism is an excellent and amazing tool for graphically illustrating how there are seven distinct colours in white light.

  • Parallelograms make up a prism's side faces (4-sided shapes with opposite sides parallel). A cube is a prism because of the continuous, square pattern that runs throughout the length. Due to the regular cross-section, each of the aforementioned examples is a Regular Prism (in other words, it is a shape with edge lengths that are equal in size and angles). It is an unusual pentagonal prism that lacks "regularity" in its cross-sectional shape.



Oblique Vs Right Prism

When the two ends are perfectly aligned, it is a right prism. If not, it is an Oblique Prism.

Surface Area of a Prism = 2 × Area of the base + Base Perimeter × Length

A prism basically refracts the light, light is refracted as soon as it enters a prism. Due to the distribution of colours throughout the spectrum, you may see them (spread out).

After all, each spectrum colour is refracted distinctly.

Right Prism Vs Oblique Prism

Right Prism Vs Oblique Prism

What is Refraction of Light?

Light refraction, as used in physics, is the optical phenomenon in which light is bent as it passes through another substance. When a light beam passes through the atmosphere and comes across the polished surface of a glass prism, for example, refraction takes place. 

Prism Showing Refraction of Light

Prism Showing Refraction of Light

The angle of the deviation of light in this situation will be determined by the glass's refractive index. The deviation of light also depends on the incidence angle at which it strikes the prism's surface.

Prism Making Light Disperse

Prism Making Light Disperse

What Connection Exists Between the Color of Light and its Wavelength?

Each colour in the visible light spectrum has a unique wavelength and is made up of various colours. In fact, the human eye is capable of perceiving wavelengths between 390 and 700 nm. In that sequence, the following colours represent this spectrum of wavelengths:

Purple, Blue, Cyan, Green, Yellow, Orange, and Red

However, wavelengths beyond the visible light spectrum are invisible to the human eye. For instance, UV radiations, which are not visible, are emitted at wavelengths below 390 nm. This explains why infrared emissions at longer wavelengths are invisible to us.

Diagram Your Rainbows

Let us look at the process of how to use a prism in order to get a spectrum of light.


  • Prism

  • White paper

  • Colourful pencils

  • Sunlight

Students assemble their prism diagrams in pairs. They make their prism display colours by placing white paper on a table and using sunshine. The other student draws pictures of the colourful light emanating from the prism with coloured pencils. To see whether they can acquire the colours in a different order or the light in a different shape, students experiment with a variety of setups.

How do Prisms Work?

The underlying scientific idea is that the refractive index of the prism is a function of the wavelength of the light that passes through it. As a result, when a beam of white light strikes a prism, each of the wavelengths that make up the white beam's full range of colours will deviate at a certain angle. In other words, a vibrant rainbow will be formed when the white light is split. This optical phenomenon is comparable to the rainbows in the sky that are caused by water droplets diffracting the light.

How to Use a Prism?

It is quite simple to understand how to use a prism. Look at the steps given below.


  • A variety of pattern-different paper scraps

  • A range of shapes and sizes of prisms

Investigate how placing prisms on top of various patterned papers change the pattern's direction. Examine the ways through each prism and consider how the prisms' various sizes and shapes vary in how the designs look. Encourage children to describe why they think the prism affects how the pattern looks.

You can use a torch if the weather is not sunny to understand how prisms work. Make a slit across a white card using the dark card. Placing the card will allow a thin light beam from the Sun to pass through. When you can see the light split into its many colours, place the prism over the light source and rotate it.


Prism is a fun and educational concept to learn. It is a three-dimensional mathematical shape. A triangular block of glass or perspex called a prism divides light into various colours. It is a very important topic as well. We study prism as a concept in optics(a branch in physics). This article made the concept of prism quite understandable and easy. We discussed what a prism does, what is refraction light and many more important things related to prisms. We hope you enjoyed reading this article, in case of any doubts, feel free to ask in the comments.

FAQs on Prism

1. How much time does it take for light to reach Earth?

It is an interesting fact that it takes 8 minutes and 20 seconds for light to reach Earth from the Sun. 

2. How do light waves travel?

Light waves can travel through a vacuum. They are considered to be quite powerful and unique being able to travel through a vacuum.

3. Which are faster; Light waves or sound waves?

Light waves are much faster than sound waves. It is a known fact that light travels faster than sound and that is why we see lightning first then hear the thundering.