Total internal reflection zero

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In total internal reflection (TIR), all incident light energy is reflected back into the original medium, resulting in no energy loss, unlike in refraction where some energy is transmitted and some is reflected. This phenomenon occurs because Snell's Law dictates that the sine of the angle cannot exceed 1, preventing refraction at steep angles. When light transitions between different media, it changes direction, and at acute angles, it reflects entirely instead of refracting. This principle explains visual effects like the twinkling of water and the sparkling of bubbles, which occur during TIR. Overall, TIR demonstrates that energy is conserved as it reflects rather than refracts.
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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