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CH 22/23

CH 22/23. Mr. Jackson 5-3-12. What is Light. Light is an EM wave (not requiring a medium) EM waves are produced by radiation which is the transfer of energy in the form of a wave. Light Speed. The Speed of Sound was 343m/sec The speed of light is 300,000,000m/sec

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CH 22/23

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  1. CH 22/23 Mr. Jackson 5-3-12

  2. What is Light • Light is an EM wave (not requiring a medium) • EM waves are produced by radiation which is the transfer of energy in the form of a wave

  3. Light Speed • The Speed of Sound was 343m/sec • The speed of light is 300,000,000m/sec • This is 880,000 times faster than the speed of sound • If you could run at the speed of light you could circumnavigate the earth 7.5 times per second • It takes 8.3 min for the sun to transmit light to the earth

  4. EM Spectrum • The entire range of EM waves is called the EM spectrum

  5. Radio Waves • Longest Wavelength (over 30 cm) • FM and AM radio and analog television signals are broadcast using Radio waves

  6. Microwaves • Wavelength between 1mm and 30 cm • Microwave ovens, Cell Phones and Radar( Used to detect speed of a car) use microwaves.

  7. Infrared • Used to detect heat • Military and Fire • Kitchens to keep food Hot • IR thermometer

  8. Visible light • The only part of the EM Spectrum you can see. • The colors are Red, Orange, Yellow, Green, Blue, Indigo, Violet • Roy G. Biv

  9. Ultraviolet • More violet than violet (Ultra Purple) • Commonly known as UV • Tanning beds, black light, ect. • UV CAUSES CANCER!!! • UV Causes sunburn • UV does allow the body to utilize vitamin D

  10. X Rays • Will pass through many materials • Used in medical diagnostics • Used for security devices in airports ect.

  11. Gamma Rays • Have the shortest wavelength • Penetrate most materials easily • Used for radiation treatment for cancer • Also used to kill harmful bacteria in food

  12. Reflection • Light waves can be reflected by using a mirror • The law of reflection states that the angle of incidence is equal to the angle of reflection • Incidence is the arrival of a beam of light at a surface

  13. Light Source vs. Reflection • Objects that produce visible light are called luminous • Objects that are visible but do not produce light are called illuminated

  14. Absorption and Scattering • When light becomes dimmer while traveling through a medium such as air is Absorption • Scattering is where light becomes dimmer due to the particles of light spreading out

  15. Refraction • Refraction of light is the bending of light • This process occurs because light travels slower through solids and liquids than it does air • Refraction will separate visible light into the 7 primary colors by using a prism

  16. Types of Objects and their interaction with light • A Transparent object allows light to be transmitted through the object (Glass) • A Translucent object transmits light but not an image ( Wax Paper) • An opaque object will not transmit light or an image

  17. Color • Red, Blue and Green are the Primary colors of light. • When the colors of light combine they undergo color addition which produce the secondary colors of light which are Magenta, Cyan, and Yellow • Television screens produce the colors Red, Blue and Green. New Televisions with 3-D Technology and LED Technology use Yellow in the pixels to produce more vibrant color schemes • When all the Primary colors mix they produce White light

  18. Pigments • The primary pigments are Yellow, Magenta, and Cyan and by the process of color subtraction they produce the Primary Colors of light • When they all mix together they produce Black

  19. Mirrors • A plane mirror has a flat surface. Images appear the same size but are reversed right to left • Concave Mirror makes objects appear smaller shaped like the inside of a spoon • Convex Mirror Makes objects appear larger shaped like the back of a spoon

  20. Lenses • A lens is a transparent object that refracts light • Convex Lenses is thick in the middle and narrow on the edge. Used in magnifying lenses and in cameras • Concave Lenses are thin in the middle and thick on the edges. Used in eyeglasses and microscopes

  21. Vision Problems • Nearsightedness is a condition where they eye is too long. These people see things up close but not far away • Farsightedness is there the eye is too short. These people can see far away but not up close • Color Blindness where the cones that receive color do not function properly

  22. Surgical Eye Correction • Lasik is a surgical procedure where laser is used to reshape the lens of the eye. It is minimally invasive although the cornea is cut. • PRK is a surgical procedure that is used to reshape the lens. In this procedure the cornea is burned away by a laser and the recovery is longer however the correction tends to last longer

  23. Laser • Produces intense light of only 1 wavelength and color. The waves in a laser behave as 1 wave

  24. Optical fiber • Thin glass tubes that transmit light. • Used for data and voice communication also used for video • Light in a pipe

  25. Polarized light • Polarized light is light that has passed through a filter and only 1 plane of the light is allowed to pass.

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