Total internal reflection zero

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Discussion Overview

The discussion centers around the phenomenon of total internal reflection (TIR) in the context of light refraction and energy conservation. Participants explore the differences between energy behavior in refraction versus TIR, questioning whether energy loss occurs in TIR and the conditions under which TIR happens.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • Some participants question whether energy is lost during refraction, suggesting that measuring only transmitted light may lead to the perception of energy loss.
  • Others argue that in total internal reflection, the reflected light equals the total incident energy, implying no energy loss occurs.
  • One participant notes that refraction involves both reflection and transmission, while TIR only involves reflection due to the constraints of Snell's Law.
  • Another participant explains that the inability to have a refracted wave at certain angles leads to total reflection, emphasizing the relationship between angle and energy direction.
  • There is a mention of the wavelength and speed changes in different mediums affecting energy flow directions, with bubbles serving as an example of TIR.

Areas of Agreement / Disagreement

Participants express differing views on whether energy loss occurs in total internal reflection and the reasons behind the behavior of light in refraction versus TIR. The discussion remains unresolved with multiple competing perspectives.

Contextual Notes

Participants reference Snell's Law and the conditions under which total internal reflection occurs, but do not fully resolve the implications of energy conservation in these contexts. There is an acknowledgment of the complexity involved in the behavior of light at different angles and mediums.

kimmy510
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How is that in refraction of light energy is lost but not in case of total internal reflection?
Is the loss in total internal reflection exactly zero?
 
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Energy is never lost.

In refraction some of the light is reflected and some transmitted. If you only measure the transmitted light, you would measure an energy loss.

In total internal reflection you are measuring the reflected light, which is equal to the total incident energy.
 
why is that in refraction both refraction and reflection takes place but in case of total internal reflaction only reflection takes place but not refraction?
 
On a possibly superficial level, it's because Snells Law applies and the Sine of an angle can't be bigger than 1. That means there can't be a refracted wave and all the energy has to be reflected.
 
kimmy510 said:
How is that in refraction of light energy is lost [...]

Why do you claim this?
 
sophiecentaur said:
On a possibly superficial level, it's because Snells Law applies and the Sine of an angle can't be bigger than 1. That means there can't be a refracted wave and all the energy has to be reflected.

In other words, light changes direction when it changes between different mediums. If in this change of direction it happens to point back away from the medium (because of a very acute angle) then it never travels on a line that goes through the medium.

This is what makes water appear to twinkle, flashes of total reflection as the water positions itself at this acute angle with incoming light.
 
The point is that the wavelength / speed changes and that sometimes has knock-ons involving the possible directions in which energy can flow as waves.

Bubbles are a good example of TIR, when they sparkle. Cheers! Hic.
 

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