Reflection and Refraction

Dispersion

How refraction separates white light into its component colors

Dispersion lesson illustration

Review - Name the angle of incidence and the angle of refraction

Dispersion lesson illustration

 

Dispersion PHET - showmethephysics.com

Assessment

 

 

About Light

| Onsite |

 

Newton proved that white light is a blend
of all the colors of the rainbow

Dispersion lesson illustration

 

 

 

White Light Animation

(Right Click, Save As)

Penn State

Dispersion lesson illustration

 

 

 

2. Dispersion – separation of polychromatic light into its component wavelengths (colors)


Dispersion lesson illustration

Wikipedia - Public Domain

 

 

Trivia

What famous album cover
has a prism on the front? Their big hit?

 

 

 

Each Color has

A Different Wavelength

prism

 

NASA

 

 

Red - fastest
(slowed least),
bent least

Violet - slowest
(slowed most),
bent most


Dispersion lesson illustration

Lucas V. Barbosa

 

 

Dispersion lesson illustration

 

 

Dispersive Medium – medium in which the velocity of wave depends on frequency

(makes rainbows)

Dispersion lesson illustration

ex) Glass, water 

 

Nondispersive - Air

 

Dispersion lesson illustration

 

 

Refraction with
Polychromatic Light
(Angle, Index of refraction)
Molecular Expressions  - FSU

 

 

 

Dispersion lesson illustration

http://www.freeimages.co.uk/

 

 

 

Review

What is the name for this special kind of reflection?

Dispersion lesson illustration

Wikipedia 

 

 

 

Total internal reflection in a bar of PMMA.
The laser is HeNe laser

 

Review

Cross out all the ray diagrams that are incorrect. Justify your answers.

Dispersion lesson illustration 

Regents June 2014

The Nasty Feud Between Isaac Newton and Robert Hooke


Total Internal Reflection
/Dispersion Assessment

 

Dispersion lesson illustration

Enrichment

Review Video

| Onsite |

 

Refraction/Dispersion Simulations

University of Utah

 

 

Check Your Understanding

5 quick questions — pick an answer to see if you’re right.

1. What is dispersion?

2. White light passes through a glass prism. Which color is bent the most?

3. Inside a glass prism, which color of light travels fastest?

4. A dispersive medium is one in which wave speed depends on frequency. Which of these is NOT dispersive for light?

5. A student says a prism adds colors to white light. What did Newton actually show?

NYSSLS Regents Practice · Waves · Dispersion

Splitting White Light With a Prism

White light enters a glass prism. In this glass, the index of refraction is 1.51 for red light and 1.53 for violet light.

Which color is bent (refracted) the most, and why?

▶ Want a challenge? Open 6 more Regents-style questions  (harder · mixed formats)

Challenge score: 0 / 6

Multiple choice

C1. Which color travels fastest in the glass?

Substitute values

C2. Substitute numerical values into a mathematical representation that can be used to determine the speed of red light in this glass. Then calculate the speed.

v = × 108 m/s = × 108 m/s
Support or Refute · Justify

C3. A student makes the following claim.

Claim: A prism made of a material whose index of refraction is exactly the same for every color would still separate white light into a spectrum.

Place a check mark in either the Support or Refute box. Justify your response.

Determine the value

C4. Red light has a wavelength of 700. nm in air. Determine its wavelength inside this glass, in nanometers.

λ = nm
Multiple choice

C5. Would a prism-shaped region of vacuum disperse white light?

Constructed response

C6. A simple glass camera lens produces colored fringes around objects because different colors focus at different distances. Explain how dispersion causes this, and identify one benefit and one drawback of fixing it by combining two lenses made of different types of glass.

Wave Nature of Light →