Huygens Principle

Works Cited

Hewitt, Paul G. "Ch.31 Diffraction and Light." Conceptual Physics: The High School Physics Program. Needham, MA: Prentice Hall, 2002. 622-36. Print.

THE END

Answers:

False

Increase, decrease or neutralize

Parallel slits

True

Quiz

True or False: Huygen's principle is the idea that light waves that spread from a point source may not be regarded as overlapping.

Fill in the Blank: Within an interference pattern, wave amplitudes may be ________, _________, or _____________

Fill in the Blank: a multitude of closely spaced __________ ______ make up what is called a diffraction grating

True or False: A beam of light that has the same frequency, phase, and direction is a laser.

Laser Light

The Hologram

Hologram- a three-dimensional version of a photograph that contains the whole message or entire picture in every portion of its surface

To the naked eye, it appears

to be an imageless piece of

transparent film, but on its

surface is a pattern of

microscopic interference

fringes

Young's Experiment

Diffraction Grating- a multitude of closely spaced parallel slits

Interference from Thin Films

Young's Interference

Experiment

Interference provides the principal method for measuring the wavelengths of light

In 1801, Thomas Young discovered that when monochromatic light-light from a single color- was directed through two closely spaced pinholes, the screen would show fringes of brightness and darkness

Laser Light

Interference From Thin Films

Incoherent Light- The crests and troughs of the light waves don't line up with one another

Iridescence- the phenomenon in which the interference of light waves of mixed frequencies produces a spectrum of color

A thin film, such as a soap bubble, has two closely spaced surfaces. Therefore, light that comes from one surface cancels out light from another.

Coherent Light- A beam of light that has the same frequency, phase, and direction

Laser- a converter of energy which produces coherent light

INTERFERENCE PATTERNS

INTERFERENCE

• It is the idea that wave fronts are made up of tinier wave fronts

Huygens Principle

• In an interference pattern, wave amplitudes may be increased, decreased, or neutralized.
• Interference pattern is produced by the two sets of waves that result cross each other.
• Constructive Interference is when the crest of one wave overlaps the crest of another and their individual effects add together
• Destructive Interference is when the crest of one wave overlaps the trough of another, and their individual effects are reduced

• Huygens Principle states that light waves spreading out from a point source may be regarded as the overlapping of tiny secondary wavelets. Every point on any wave front may be regarded as a new pont source of secondary waves

DIFFRACTION

• Diffraction is any bending of a wave by means other than reflection or refraction
• The extent of difffraction depends on the relative size of wavelength compared with the size of the obstruction that casts the shadow.
• When light is of a single color, diffraction can produce sharp diffraction fringes.

DIFFRACTION

EXAMPLES

Ch.31 Diffraction and Interference