INTRODUCTION
Introduction to Prisms
Triangular prism
Rectangular prism
Hexagonal prism
What is a prism?
A prism is a polyhedron with two identical bases and
flat sides. The bases are polygons (triangles, squares,
pentagons, etc.), and the sides are parallelograms.
Prisms are named after the shape of their base (e.g.,
triangular prism, square prism).
Types of prisms:
* Right prisms: Sides perpendicular to bases.
* Oblique prisms: Sides not perpendicular to bases.
* Regular prisms: Bases are regular polygons
* Real-world examples: Optical prisms (cameras,
binoculars), decorative crystal prisms, some building
designs.
Properties of Prisms
* Faces: Two bases + rectangular sides (number of
sides = number of base sides).
* Edges: Lines where faces meet.
* Vertices: Points where edges meet.
* Cross-sections: Slicing parallel to the base creates
an identical cross-section
Volume of Prisms
* Formula: Volume = Area of base × Height
* Explanation: Find the base's area, multiply by the
prism's height (perpendicular distance between bases).
* Examples:
* Triangular prism: Base area 10 cm², height 5 cm.
Volume = 10 cm² × 5 cm = 50 cm³
* Cube: Side 4 cm. Volume = 4 cm × 4 cm × 4 cm =
64 cm³
Surface Area of Prisms
* Formula: Surface Area = Lateral Area + 2 × Base
Area
* Explanation:
* Lateral Area: Sum of rectangular side areas.
* Base Area: Area of one base.
* Example:
* Rectangular prism: 3 cm, 4 cm, 5 cm. Surface Area =
2(3×4 + 3×5 + 4×5) = 94 cm²
Prisms and Light
Refraction
* Refraction: Light bends as it passes from one
medium to another (e.g., air to glass). The angle of
bending depends on the angle of incidence and the
refractive indices of the materials.
* Dispersion: White light separates into colors
because each color bends slightly differently.
Types of Optical Prisms
* Triangular prisms:
Dispersion and reflection
* Right-angle prisms:
Total internal reflection (used in binoculars,
cameras).
* Dispersion prisms:
Maximize color separation
Applications in Technology
* Cameras: Direct light to the image sensor.
* Binoculars: Invert and magnify the image.
* Spectrometers: Separate light into wavelengths
for analysis.
* Fiber optics: Internal reflection within optical
fibers.