Chapter+27+and+28

​**Key Definitions** **: **. 1. __**Photon-**__In the particale model of electromagnetic radiation, a particale that travels only at the speed of light and whose energy is related to the frequency of the radiation in the wave model. 2.**__Transparent__**- term applied to materials that allow light to pass through them in straight lines. 3. **__Opaque-__** term applied to materials that absorb light without remission, and consequently do not allow light through them. 4. __**Polarization**__- the vibrations in a tranverse wave, usually by filtering out waves of other directions. 5. **__White light__-** light that is a combination of all the colors. under white light, white light white objects appear white and colored objects appear in their individual colors

**Notes:** Write down at least 10 key points from the chapter.
 * Newton coined the term spectrum to discribe the spread of color cast by a prism in sunlight.
 * Black is not a color but rather an absence of light. Objects appear black because they absorb light at all frequencies
 * When light shines on an object, some of the rays may be stopped while others pass on in a straight line.
 * Sunlight is a white light
 * When two colors are combines to produce white they are called complimantary
 * The speed of light is 300,000,000 per second.
 * Light has a dual nature, part particle part wave
 * When light shines on an object some of the rays may be stopped while others pass on in a straight line path.
 * Light will pass through a pair of polarizing filters when their polarization axes are aligned but nopt when they are crossed at right angles.
 * During the day the primary source of light is the sun

**Pictures: **





Links:
 * [] (how light works)
 * [] (what are colors)


 * Test Questions: **
 * 1) True or False: A photon travels at the speed of sound.
 * 2) True or False: Glass and water allow light pass through in straight lines.
 * 3) What colors make up white light? A.Red,Blue,Green B.Red,Yellow,Orange C.Blue,Yellow, Purple
 * 4) True or False: Wood is an Opaque material.
 * 5) Who was the first to make a systematic study of colors?
 * 6) Electromagnetic waves of frequencies higher than those of violetare called what? A. infrared B. Ultraviolet
 * 7) True or False: pigment selectively absorbs colored light?
 * 8) How long does it take light to travel 1 light-year? A. 1 second B. 1 hour C. 1 year D. 2 years
 * 9) True or False: Red + Green= Yellow?

**Record the aswers to the above questions at the link below** Answers to Test Questions