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Intermolecular bonds between
water molecules are very strong

kentchemistry YouTube Channel

E. Wave Nature of Light

2 Competing Theories:

1. particle	2. wave
	Wikimedia - (c) 2002 B. Crowell, GFDL licensed

Behavior of Light Supporting Wave Theory

1. Diffraction – light spreads out into the region behind an obstacle

TuningBeatsYT.mov

2. Interference – Young’s Double Slit - Late 1800's

Pattern created by a single light wave
 passing through 2 small slits!

Claus_Jönsson_Interferenz.jpg‎
(146 × 200 pixels, file size: 1 KB, MIME type: image/jpeg)

Prof Dr. Claus Jönsson

St. Mary's Physics

λ/d = x/L

St. Mary's Physics

Monochromatic Coherent
Light Source was used

Which light source is coherent?

June 1997 Regents Test

Double Slit - Wavelength Difference-
Michael Fowler Flashlets

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St. Mary's Physics

If you draw a line from each slit to the 1st order bright line, you will notice that one line is longer than the other.

The difference between these two lines is 1λ.

Destructive Interference
 1/2, 1 1/2, 2 1/2 ...
Wavelength difference

Constructive Interference causes ...     Bright Lines    Destructive Interference causes...      Dark Lines

Polarization

Enrichment

Ex) Calculate the distance between two slits in a Double Slit Experiment if the wavelength of the light used is is 5 x 10^-7 m and the distance between the central maximum and the first order bright line is 2 x 10^-2 m. The distance from the slits to the screen is 4 meters.

(5 x 10^-7 m)/d = (2 x 10^-2 m)/4 m


Answer d = 1 x 10^-4 m
 

Question: If they give you d, L and x and asked you to find the COLOR of the light used, What would you do? Where would you go to find the color?

Answer:

1. Solve for λ use Young's Equation

2. Use 3 x 10⁸ m/s = fλ to find the colors frequency

3. Look up the color on page 2 Ref.