Resource Lesson
Dispersion
Printer Friendly Version
As you can see in the diagram to the right each wavelength in the electromagnetic radiation actually has a unique
index of refraction
in any given specific medium. The value of the index is an indication of how closely the frequency of the electromagnetic radiation matches the resonance frequency of the electrons in the medium. The closer these values coincide, the greater the value of
n
and the greater the
interaction between the photons with the electrons in the medium
.
College Physics
, Wilson and Buffa, page 693
These distinctive values for the refractive index,
n
, cause white light to be dispersed, or break into its component frequencies, as it travels through an optically dense medium.
This effect is best noticed when light enters a medium obliquely, as in the triangular prism shown below. Since the red light interacts least with the electrons in the glass, it emerges first and is least bent. While the violet photons interact the most strongly with the electrons in the glass, emerge last, and are bent, or deviated from their original path, at the largest angle. This produces the familiar spectrum of light you see when sunlight passes through crystal chandeliers.
Physlet Animations
dispersion through a glass prism
dispersion through a glass slab
Continuing with the information learned in the lesson on
Snell's Law
we will now examine the angles resulting when polychromatic light passes through a transparent substance.
Refer to the following information for the next three questions.
Polychromatic magenta light enters a 30º-60º-90º triangular piece of flint glass perpendicularly as shown below.
Will the beams "bend" as they enter the prism or do they continue along a straight path?
Within the flint glass, the blue (460 nm) and red (660 nm) component wavelengths have different indices of refraction: blue n = 1.665; red n = 1.615. What is the angle between the component colors when they emerge from the prism?
Why would crown glass not produce as nice a spectrum?
Related Documents
Lab:
Labs -
A Simple Microscope
Labs -
Blank Ray Diagrams for Converging Lenses
Labs -
Blank Ray Diagrams for Converging, Concave, Mirrors
Labs -
Blank Ray Diagrams for Diverging Lenses
Labs -
Blank Ray Diagrams for Diverging, Convex, Mirrors
Labs -
Determining the Focal Length of a Converging Lens
Labs -
Index of Refraction: Glass
Labs -
Index of Refraction: Water
Labs -
Least Time Activity
Labs -
Man and the Mirror
Labs -
Man and the Mirror: Sample Ray Diagram
Labs -
Ray Diagrams for Converging Lenses
Labs -
Ray Diagrams for Converging Mirrors
Labs -
Ray Diagrams for Diverging Lenses
Labs -
Ray Diagrams for Diverging Mirrors
Labs -
Reflections of a Triangle
Labs -
Spherical Mirror Lab
Labs -
Student Lens Lab
Labs -
Target Practice - Revised
Resource Lesson:
RL -
A Derivation of Snell's Law
RL -
Converging Lens Examples
RL -
Converging Lenses
RL -
Demonstration: Infinite Images
RL -
Demonstration: Real Images
RL -
Demonstration: Virtual Images
RL -
Diverging Lenses
RL -
Double Lens Systems
RL -
Lensmaker Equation
RL -
Mirror Equation
RL -
Properties of Plane Mirrors
RL -
Refraction of Light
RL -
Refraction Phenomena
RL -
Snell's Law
RL -
Snell's Law: Derivation
RL -
Spherical Mirrors
RL -
Thin Lens Equation
Review:
REV -
Drill: Reflection and Mirrors
REV -
Mirror Properties
REV -
Physics I Honors: 2nd 9-week notebook
REV -
Physics I: 2nd 9-week notebook
REV -
Spherical Lens Properties
Worksheet:
APP -
Enlightened
APP -
Reflections
APP -
The Librarian
APP -
The Starlet
CP -
Lenses
CP -
Plane Mirror Reflections
CP -
Refraction of Light
CP -
Snell's Law
CP -
Snell's Law
NT -
Image Distances
NT -
Laser Fishing
NT -
Mirror Height
NT -
Mirror Length
NT -
Reflection
NT -
Underwater Vision
WS -
An Extension of Snell's Law
WS -
Basic Principles of Refraction
WS -
Converging Lens Vocabulary
WS -
Diverging Lens Vocabulary
WS -
Lensmaker Equation
WS -
Plane Mirror Reflections
WS -
Refraction and Critical Angles
WS -
Refraction Phenomena
WS -
Refraction Through a Circular Disk
WS -
Refraction Through a Glass Plate
WS -
Refraction Through a Triangle
WS -
Snell's Law Calculations
WS -
Spherical Mirror Equation #1
WS -
Spherical Mirror Equation #2
WS -
Spherical Mirrors: Image Patterns
WS -
Thin Lens Equation #1: Converging Lenses
WS -
Thin Lens Equation #2: Converging Lenses
WS -
Thin Lens Equation #3: Both Types
WS -
Thin Lens Equation #4: Both Types
WS -
Two-Lens Worksheet
WS -
Two-Mirror Worksheet
TB -
27B: Properties of Light and Refraction
TB -
Refraction Phenomena Reading Questions
PhysicsLAB
Copyright © 1997-2020
Catharine H. Colwell
All rights reserved.
Application Programmer
Mark Acton