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Total internal reflection (3)

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Chithra VM

This document discusses total internal reflection and some of its applications. Total internal reflection occurs when light travels from an optically denser medium to a less dense medium at an angle greater than the critical angle, causing the entire light ray to be reflected back into the denser medium. This phenomenon is used to create mirages by light rays curving downward in air of varying densities near the ground. Optical fibers are also able to transmit light along their length due to total internal reflection of light off the fiber walls. Cut diamonds are designed to take advantage of total internal reflection to reflect light internally and appear brilliant.

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TOTAL INTERNAL REFLECTION & ITS APPLICATIONS Presented by Chithra V M Physical Science GCTE Thycaud
Optical density Ability of a medium to refract light Two types of medium-rarer medium and denser medium Rarer medium has lower refractive index Denser medium has higher refractive index Speed of light is higher in rarer medium than in denser medium
Bending of light takes place when light passes obliquely from one transparent medium to another.
When light ray enters from a denser medium to a rarer medium it bends away from the normal
As angle of incidence (i) increases so does the angle of refraction At a particular angle of incidence the angle of reflection becomes 900 Refracted ray grazes the surface at the interface between the two media The angle of incidence for which angle of refraction becomes 900 CRITICAL ANGLE
When angle of incidence becomes greater than critical angle the incident ray is totally reflected
Total internal reflection When a ray of light travels from denser medium to rarer medium ,if the angle of incidence is greater than the critical angle the entire ray is reflected into the same medium by obeying the laws of reflection . Conditions for total internal reflection Light must travel from denser medium to rarer medium The angle of incidence must be greater than the critical angle
Total internal reflection (3)
Mirage The optical illusion due to total internal reflection On sunny days the air near the ground is cooler than that higher up The light rays curve downward, producing a superior image
Optical fiber Thin hair like structure Light enters one end of the wall of the fiber strikes at less than critical angle Light undergoes repeated total internal reflection Light emerges through the other end of fiber
Diamond The critical angle of diamond is very small The cut of diamond favors total internal reflection Rays entering the top of diamond reflects internally
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Total internal reflection (3)

  • 1. TOTAL INTERNAL REFLECTION & ITS APPLICATIONS Presented by Chithra V M Physical Science GCTE Thycaud
  • 2. Optical density Ability of a medium to refract light Two types of medium-rarer medium and denser medium Rarer medium has lower refractive index Denser medium has higher refractive index Speed of light is higher in rarer medium than in denser medium
  • 3. Bending of light takes place when light passes obliquely from one transparent medium to another.
  • 4. When light ray enters from a denser medium to a rarer medium it bends away from the normal
  • 5. As angle of incidence (i) increases so does the angle of refraction At a particular angle of incidence the angle of reflection becomes 900 Refracted ray grazes the surface at the interface between the two media The angle of incidence for which angle of refraction becomes 900 CRITICAL ANGLE
  • 6. When angle of incidence becomes greater than critical angle the incident ray is totally reflected
  • 7. Total internal reflection When a ray of light travels from denser medium to rarer medium ,if the angle of incidence is greater than the critical angle the entire ray is reflected into the same medium by obeying the laws of reflection . Conditions for total internal reflection Light must travel from denser medium to rarer medium The angle of incidence must be greater than the critical angle
  • 9. Mirage The optical illusion due to total internal reflection On sunny days the air near the ground is cooler than that higher up The light rays curve downward, producing a superior image
  • 10. Optical fiber Thin hair like structure Light enters one end of the wall of the fiber strikes at less than critical angle Light undergoes repeated total internal reflection Light emerges through the other end of fiber
  • 11. Diamond The critical angle of diamond is very small The cut of diamond favors total internal reflection Rays entering the top of diamond reflects internally