22 Sep 2021

Prism – Definition, Elements, Prism Types, Calculations, and More

What is a Prism?

• The Prism is a type of irregular polyhedra, i.e., geometric shapes with all its flat faces.
• But what differentiates a prism from, for example, a pyramid?
• We will learn the characteristics of prisms, the elements that form them, the types of prisms that exist, and what criteria they are classifying.
• We will see how the area and volume of a prism calculate.
• Remember that polyhedra are geometric bodies whose faces are flat. All facets of a polyhedron are polygons.
• When their faces are all the same, it is a regular polyhedron; if, on the other hand, their faces are different.
• We face it with an irregular polyhedron, as in the case of the prism.

Elements of Prism

The parts of a prism are:

1. Bases (B): each prism has two bases, equal and parallel.
2. Side faces (C): the parallelograms between the two floors.
3. Edge (A): the line segment where two faces meet (both side faces and feet).
4. Vertex (V): the point where three or more edges intersect.
5. Height (h): the distance between the two bases.

Types of Prisms

We can classify the prisms according to four different criteria:

• Regular or irregular: a prism is standard if its bases are regular polygons and irregular if they are irregular polygons.
• Straight or oblique: The prism is linear when its axis is perpendicular to the bases and oblique when the angle between the axis and the base is different from 90 °.
• Convex or concave: it is convex if its bases are convex polygons and concave if, on the contrary, they are concave polygons.

How to calculate the area of a Prism

• To calculate its area, you have to add the size of each of its faces.
• If it is a straight, it can calculate the area with the following formula:
• Area = 2 × A b + P b × h

Where:

• A b is the area of the base
• P b is the perimeter of the base
• h is the height of the prism

How to calculate the volume of a prism

• The volume of a prism is the product of base area (A b) and the height (h):
• Volume = A b × h

Reflecting prisms

• In reflector prisms where scattering is not desirable, the light beam introduces.
• So that at least one total internal reflection occurs to change the direction of propagation, the orientation of the image, or both.
• In the previous equations, when we have calculated the minimum dispersion.
• We realize that it is independent of the refractive index and the wavelength.
• The reflection will occur without any color preference, and the prism is called achromatic.
• The following figures show some of the many reflector prisms out there, which construct BSC-2 p C-1 glass.

Amici’s Prism

• It is a truncated orthogonal prime with an added roof section on the hypotenuse side.
• It’s most common use has the effect of splitting the image in half and swapping the portions right to left.
• These prisms are expensive because they must keep the apical angle within approximately 3 to 4 arc seconds.
• Otherwise, you will get a bothersome double image.
• It is often used in a simple telescope system to correct for lens reversal.

Penta Prism

• It will deflect the beam by 90º without affecting the orientation of the image.
• Note that two of its surfaces must be silver.
• We can you these prisms as reflectors at the ends of short-range finders.