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Light

Light. Light. Investigation 1. Spectrophotometer. An instrument that sends a beam of light at a specific wavelength through liquid to see how much light it is absorbed or transmitted. Transmittance. Transmittance is the ability of light to pass through a medium

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Light

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  1. Light

  2. Light Investigation 1

  3. Spectrophotometer • An instrument that sends a beam of light at a specific wavelength through liquid to see how much light it is absorbed or transmitted

  4. Transmittance • Transmittance is the ability of light to pass through a medium • is reported as a value between 0 and 100% • 100% indicates that all of the light is transmitted through the liquid • A value less than 100% indicates that some light is absorbed by the light

  5. Absorbance • Absorbance- to take light in and not reflect or refract it • is reported in a value from 0 to 2.0 • 2.0 indicates that all of the light is absorbed • Between 0 and 2.0 indicates that only some light is absorbed

  6. Relationship between Absorption and Transmission of light through a transparent substance • There is an inverse relationship between amount of light that is transmitted versus that which is absorbed as light interacts with a transparent liquid • The more light that is transmitted, the less that is absorbed. • As more light is absorbed, less is transmitted through the transparent medium

  7. Light Investigation 2

  8. Reflection • Law of Reflection- the angle at which light hits an object is equal to the angle at which light is reflected from the object • Angle of incidence- angle at which light hits an object • Angle of reflection- angle at which light is reflected from the object Law of Reflection states that these two angles are EQUAL

  9. Angles of Reflection

  10. How does light wave interact with objects that reflect light? • Objects that neither absorb nor transmit light reflect light • When a light wave interacts with an object that reflects light, the angle at which the wave is reflected off the object (angle of reflection) is equal to the angle at which it encounters the object (angle incidences) • Law of Reflection • This is true regardless of the angle at which the wave strike the object.

  11. Light Investigation 3

  12. Absorbance through different Colors • Wavelengths of light are absorbed and reflected by different colored opaque objects • Red, green, blue filters • Each filter only allows a particular wavelength to pass through • The color of the filter indicates the wavelength that can pass through • Red filter only allows red wavelengths to pass through

  13. How does wavelength affect the perception of light? • The color of a transparent object or medium is determined by the wavelength of light it transmits • We perceive the object or medium as being a particular color because of those wavelengths are the ones detected by our eyes • For an opaque object the color we perceive is determined by the wavelengths of light reflected by the objects surface • Both transparent and opaque object absorb all wavelengths of light not transmitted or reflected

  14. Light Investigation 4

  15. Refraction • Refraction of light occurs whenever light travels from one medium to another • Light waves travel at different speeds through different mediums, the light waves bend as they move from one medium to another • Light waves slow as they enter water from air and bends or refracts

  16. Refraction • The angle at which the light wave enters water is called the angle of incidence • the angle at which the light wave is refracted in the water is the angle of refraction

  17. Angle of Refraction

  18. Index of Refraction • Different transparent mediums or substances refract or bend light to different degrees • Index of Refraction- a measure of the degree to which a medium refracts light • 1.00 in air

  19. Index of Refraction • Index of Refraction uses the angle value of sine (sin) to calculate the index • The greater index of refraction the greater the refraction of light

  20. How does a change in the mediums affect wavelength of light? • When light passes from one medium to another the speed of wavelengths change. • This cause the light wave to change directions- refraction • Each medium changes the speed of light in a particular way • This characteristic of the medium is called its refractive index. Air’s refractive index is 1 • The more a medium slows the passage of light, the greater its refractive index is.

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