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CHAPTER 7. LIGHT. When something produces light, it is said to be luminous . When visible light is given off as a result of high temperatures, it is said to be incandescent . Ex. Sun, lightbulb , fire Sun’s surface temperature = 5,700 o C. You already know that:.
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CHAPTER 7 LIGHT
When something produces light, it is said to be luminous. • When visible light is given off as a result of high temperatures, it is said to be incandescent. Ex. Sun, lightbulb, fire • Sun’s surface temperature = 5,700 oC
You already know that: • White light can be separated into 7 colors (ROYGBIV = spectrum) which have different wavelengths. • Red = longer wavelength and lower frequency = refracted the least of all the colors = scattered the least • Violet = shorter wavelength but higher freq. = refracted the most of all the colors = scattered more strongly
Important Facts about Light • Light travels in a straight line until it encounters another object or particles of matter; in which case, it gets: • 1. Reflected if it hits a smooth surface • 2. Transmitted = or Undergoes diffuse refection if it hits a “not-so-smooth” surface • 3. Absorbed by transparent objects.
Transparent Objects – allows light through • Opaque Objects – do not allow light to go through • It is possible for objects to absorb, transmit, or reflect light in varying degrees.
Reflection – when light bounces back • Refraction = when light changes direction at the boundary of two phases as a result of passing through one transparent material to another (like water or air) • Ex. Bending of straw in water
Light slows down when it passes from air to water. Refraction is towards the “incident ray” or the “normal ray.” • Light speeds up when it passes from water to air. Refraction is away from the “incident ray” or the “normal ray.”