1. Complementary Colors of Light
Color Addition - The production of various colors of light by the mixing of the three primary colors of light.
R + G = Y
R + B = M
G + B = C
Complementary Colors of Light
Red and Cyan
Green and Magenta
Blue and Yellow

2. Complementary Colors - Any two colors of light which when mixed together in equal intensities produce white.
R + C = R + (B + G) = White
1. Two lights are arranged above a white sheet of paper. When the lights are turned on they illuminate the entire sheet of paper (as seen in the diagram below). Each light bulb emits a primary color of light - red (R), green (G), and blue (B). Depending on which primary color of light is used, the paper will appear a different color. Express your understanding of color addition by determining the color which the sheet of paper will appear in the diagrams below.
R + G ---> Yellow
R + B ---> Magenta
B + G ---> Cyan

3. 2. If magenta light and yellow light are added together, will white light be produced? Explain.
Answer: No
Magenta light is a combination of red and blue light in equal intensities and yellow light is a combination of red and green light in equal intensities. observe the double abundance of red. Combining magenta and yellow will produce a whitish-red color - that is, pink.
Color and Vision
W - B = (R + G + B) - B = R + G = Y
C - B = (G + B) - B = G

4. Check for intelligence
1. Test your understanding of these principles of color subtraction by determining the color appearance of the same shirts if illuminated with other colors of light. Be sure to begin by determining the primary color(s) of light which are incident upon the object and then subtracting the absorbed color from the incident color(s).
Practice A: Magenta light is a mixture of red light and blue light in equal intensities. Blue light must be subtracted since it is absorbed. When subtracting blue light from red and blue light, the red remains. The shirt appears red.
(R + B) - B = R
Practice B: Red light is a primary color. Blue light would have to be subtracted if present. Since it is not present, there is no need to worry about it. Red light is reflected and the shirt appears red.

5. Practice C: Blue light is a primary color
Practice C: Blue light is a primary color. Blue light must be subtracted since it is absorbed. There is no other color left to reflect to our eyes. The shirt appears black since black is the absence of reflected light.
Primary Colors of Paint
Each of the three colors which are primary to an artist (magenta, cyan, and yellow) subtract red, green, and blue individually from an otherwise white sheet of paper. Thus,
Magenta paints absorb green light.
Cyan paints absorb red light.
Yellow paints absorb blue light.

6. Check for intelligence
1. Blue jeans appear blue because the jeans are permeated by a chemical dye. Explain the role of the dye. That is, what does the dye do (absorb or reflect) to the various frequencies of white light?

7. Blue Skies and Red Sunsets
The appearance of the sun changes with the time of day. While it may be yellow during midday, it is often found to gradually turn color as it approaches sunset. This can be explained by light scattering. As the sun approaches the horizon line, sunlight must traverse a greater distance through our atmosphere; this is demonstrated in the diagram below.

8. Polarization
A light wave is an electromagnetic wave
Polarized light waves are light waves in which the vibrations occur in a single plane. The process of
Polarization by Use of a Polaroid Filter

9. Polarization by Reflection
Polarization by Refraction

10. Check for intelligence
1. Suppose that light passes through two Polaroid filters whose polarization axes are parallel to each other. What would be the result?
The first filter will polarize the light, blocking one-half of its vibrations. The second filter will have no affect on the light. Being aligned parallel to the first filter, the second filter will let the same light waves through.
2. Consider the three pairs of sunglasses below. Identify the pair of glasses is capable of eliminating the glare resulting from sunlight reflecting off the calm waters of a lake? _________ Explain. (The polarization axes are shown by the straight lines.)
                                                                                                                                                       
Answer: A
Referring to the above question, the glare is the result of a large concentration of light aligned parallel to the water surface. To block such plane-polarized light, a filter with a vertically aligned polarization axis must be used.

11. The Electromagnetic and Visible Spectra - waves which are capable of traveling through a vacuum.
Mechanical waves require a medium in order to transport their energy, electromagnetic waves are capable of transporting energy through the vacuum of outer space. Electromagnetic waves are produced by a vibrating electric charge and as such, they consist of both an electric and a magnetic component.
Visible Light Spectrum
visible light - the mix of ROYGBIV - is sometimes referred to as white light

12. 1. A light wave is an electromagnetic wave which has both an electric and magnetic component associated with it. Electromagnetic waves are often distinguished from mechanical waves. The distinction is based on the fact that electromagnetic waves ______.
Answer: C
Electromagnetic waves are able to travel through a vacuum - a region void of matter. Mechanical waves require a medium in order to propagate from one location to another.
2. Consider the electromagnetic spectrum as you answer these three questions.
a. Which region of the electromagnetic spectrum has the highest frequency?
b. Which region of the electromagnetic spectrum has the longest wavelength?
c. Which region of the electromagnetic spectrum will travel with the fastest speed?
a. The gamma radiation region have the highest frequency.
b. The radio wave region has the longest wavelength.
c. All regions have the same speed. The speed of a wave is not dependent upon its frequency and wavelength but rather upon the properties of the medium through which it travels.
                                                                                          

13. Visible Light and the Eye's Response
Color Cones
Color can be thought of as a psychological and physiological response to light waves of a specific frequency or set of frequencies impinging upon the eye.
Light which enters the eye through the pupil ultimately strikes the inside surface of the eye known as the retina.
The retina is lined with a variety of light sensing cells known as rods and cones. While the rods on the retina are sensitive to the intensity of light

14. Light Absorption, Reflection, and Transmission
Electrons of atoms have a natural frequency at which they tend to vibrates.
Resonance
Input of energy disturbs the particles and forces the object into vibrational motion.

15. The Law of Reflection
Check for intelligence
1. Consider the diagram at the right. Which one of the angles (A, B, C, or D) is the angle of incidence? ______ Which one of the angles is the angle of reflection? ______
Angle B is the angle of incidence (angle between the incident ray and the normal). Angle C is the angle of reflection (angle between the reflected ray and the normal).

16. 2. A ray of light is incident towards a plane mirror at an angle of 30-degrees with the mirror surface. What will be the angle of reflection?
                                          
The angle of reflection is 60 degrees. (Note that the angle of incidence is not 30 degrees; it is 60 degrees since the angle of incidence is measured between the incident ray and the normal.)
                                                                                          
Snell's Law
                         
where   ("theta i") = angle of incidence
  ("theta r") = angle of refraction
ni = index of refraction of the incident medium
nr = index of refraction of the refractive medium
Snell's law applies to the refraction of light in any situation, regardless of what the two media are.

17. Given:ni = 1.00 nr = 1.33 = 45 degrees
Practice Problems
First, use a protractor to measure the angle of incidence. An appropriate measurement would be some angle close to 45-degrees.
Second, list all known values and the unknown value for which you wish to solve:
Given:ni =             nr =                     = 45 degrees
Find:        = ???
Third, list the relevant equation:
                                                  
Fourth, substitute known values into the equation and algebraically manipulate the equation in order to solve for the unknown variable - "theta r."
1.00 * sine (45 degrees) = 1.33 * sine (theta r)
= 1.33 * sine (theta r)
0.532 = sine (theta r)
sine-1 (0.532) = sine-1 ( sine (theta r))
32.1 degrees = theta r

18. Proper algebra yields to the answer of 32
Proper algebra yields to the answer of 32.1 degrees for the angle of refraction. The diagram showing the refracted ray can be viewed by clicking the button below.

22. In the case of plane mirrors, the image is said to be a virtual image.
Virtual images are images which are formed in locations where light does not actually reach.