Refraction
Refraction <ul><li>Although light travels in straight lines, it  bends  when it passes from one  medium  to another </li><...
Refraction <ul><li>Refraction  = the bending of light rays as they pass between two different media </li></ul>
Refraction <ul><li>Refraction occurs due to changes in the  speed of light  in different mediums </li></ul><ul><li>Differe...
Refraction in Water <ul><li>Light rays change direction at the surface of the water </li></ul><ul><li>The image of the che...
Speed of Light <ul><li>In a vacuum: </li></ul><ul><li>However, it is impossible for light to move at this speed when parti...
Refraction <ul><li>The particles in a medium slow down the passage of  light waves </li></ul><ul><li>Light only refracts a...
Index of Refraction <ul><li>Index of Refraction = the amount by which a  transparent  medium decreases the speed of  light...
 
Given : Speed of light in glass = 1.91 x 10 8  m/s Speed of light in vacuum = 3.00 x 10 8  m/s =  1.57 The refractive inde...
Given : Refractive index in water = 1.33 Speed of light in a vacuum = 3.00 x 10 8  m/s v  = 2.26 x 10 8  m/s The speed of ...
How Light Refracts <ul><li>The part of the light beam that hits the  medium  first will slow down first </li></ul>
Angle of Refraction <ul><li>low refractive index (e.g. air)    high refractive index (e.g. glass) </li></ul><ul><ul><li>L...
Angle of Refraction <ul><li>high refractive index (e.g. glass)    low refractive index (e.g. air) </li></ul><ul><ul><li>L...
Dispersion <ul><li>The amount of refraction is different for each  colour </li></ul><ul><li>A single beam of  white   ligh...
 
 
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Refraction

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Refraction

  1. 1. Refraction
  2. 2. Refraction <ul><li>Although light travels in straight lines, it bends when it passes from one medium to another </li></ul>Medium (plural “media”) - the material that is being used or undergoing a process
  3. 3. Refraction <ul><li>Refraction = the bending of light rays as they pass between two different media </li></ul>
  4. 4. Refraction <ul><li>Refraction occurs due to changes in the speed of light in different mediums </li></ul><ul><li>Different media slow down light by different amounts </li></ul><ul><li>The more that light slows down, the more the light is refracted </li></ul>
  5. 5. Refraction in Water <ul><li>Light rays change direction at the surface of the water </li></ul><ul><li>The image of the chest appears to be more shallow than the actual chest </li></ul>
  6. 6. Speed of Light <ul><li>In a vacuum: </li></ul><ul><li>However, it is impossible for light to move at this speed when particles get in the way… </li></ul>or
  7. 7. Refraction <ul><li>The particles in a medium slow down the passage of light waves </li></ul><ul><li>Light only refracts at the boundary when it is entering or leaving a medium </li></ul>
  8. 8. Index of Refraction <ul><li>Index of Refraction = the amount by which a transparent medium decreases the speed of light </li></ul>(since units cancel, a refractive index does not have any units) or
  9. 10. Given : Speed of light in glass = 1.91 x 10 8 m/s Speed of light in vacuum = 3.00 x 10 8 m/s = 1.57 The refractive index is 1.57 = 3.00 x 10 8 m/s 1.91 x 10 8 m/s
  10. 11. Given : Refractive index in water = 1.33 Speed of light in a vacuum = 3.00 x 10 8 m/s v = 2.26 x 10 8 m/s The speed of light in water is 2.26 x 10 8 m/s 1.33 = 3.00 x 10 8 m/s v
  11. 12. How Light Refracts <ul><li>The part of the light beam that hits the medium first will slow down first </li></ul>
  12. 13. Angle of Refraction <ul><li>low refractive index (e.g. air)  high refractive index (e.g. glass) </li></ul><ul><ul><li>Light bends towards the normal </li></ul></ul><ul><li>The angle of refraction is measured relative to the normal </li></ul>
  13. 14. Angle of Refraction <ul><li>high refractive index (e.g. glass)  low refractive index (e.g. air) </li></ul><ul><ul><li>Light bends away from the normal </li></ul></ul>
  14. 15. Dispersion <ul><li>The amount of refraction is different for each colour </li></ul><ul><li>A single beam of white light can be split into a rainbow of colours </li></ul><ul><li>Dispersion = the refraction of white light into separate wavelengths (colours) </li></ul>
  15. 18. Rainbows
  16. 19. Rainbows

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