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"No, it is not.
If any substance had a refractive index less than one, that would mean that the speed of light in that substance was greater than c . The speed of light in vacuum (always as known as c) can not be exceeded under any circumstances."
Yes it is possible!
In typical media such as glass, air, water, perspex etc, one expects to find a refractive index grater than one. Light travels through the medium by sequential absorption and re-emission by the particles in the media. Think of atoms as passing a photon along like a package in a human chain. It takes time for each atom to absorb and re-emit the photon so the speed of light is slower than in vacuum. The ratio of speed in and out of the media is the refractive index. So in almost all cases the refractive index is grater than one.
However there are some cases where the refractive index of a media can be less than one.
Plasma - the refractive index of plasma is less than one n(f)= [1-(w/f)^2]^1/2
Where n(f) is the refractive index as a function of the frequency of light which is propagating through the plasma, w = the plasma frequency.
Metals - although not transparent at visible frequencies, metal is transparent to IR frequencies, and exhibits an index less than one. This is because there is a more complex mechanism used by the atoms to pass the photon through the medium. In conductors like metal, its very complicated as magnetism and moving electrons in atoms become important.
NOTE: It is the phase velocity that becomes faster than the speed of light. The group velocity of light can never exceed the speed light! Information and energy travels with the group velocity and so violation of relativity or Maxwell's equations.
What else can I help you with?
Can relative refractive index between two media be less than unity?
No, the relative refractive index between two media cannot be less than unity. The relative refractive index is defined as the ratio of the speed of light in a vacuum to the speed of light in the medium, and since the speed of light is always slower in a medium than in a vacuum, the relative refractive index is always greater than or equal to 1.
What medium has higher refractive index?
Generally, denser mediums have higher refractive index. For example, water has a higher refractive index compared to air. Similarly, glass has a higher refractive index than water.
What is the minimum value of the refractive index?
The minimum value of the refractive index is 1, which corresponds to a vacuum. The refractive index of a medium is always greater than or equal to 1.
How is the refractive index of glass is to water is related with that of air is to water?
Each substance has an index of refraction. The index of refraction of water is about 1.3330 . The index of refraction of air at standard conditions is about 1.0003 . There is no such thing as the index of refraction of "water to air".
Is the refractive index of water wrt glass less or more than 1?
The refractive index of water with respect to glass is more than 1. This means that light travels faster in water than in glass, causing the light to bend when it passes from glass to water.
Can relative refractive index between two media be less than unity?
No, the relative refractive index between two media cannot be less than unity. The relative refractive index is defined as the ratio of the speed of light in a vacuum to the speed of light in the medium, and since the speed of light is always slower in a medium than in a vacuum, the relative refractive index is always greater than or equal to 1.
Can relative refractive index between 2 media be less than unity?
yes
What medium has higher refractive index?
Generally, denser mediums have higher refractive index. For example, water has a higher refractive index compared to air. Similarly, glass has a higher refractive index than water.
Why the refractive index of ice is lower than that of water?
The refractive index of a material is related to how light propagates through it. Ice has a lower refractive index than water because its molecular structure is less dense and more sparse compared to water. This difference in molecular arrangement affects how light interacts with the substance, leading to a lower refractive index in ice compared to water.
What is the minimum value of the refractive index?
The minimum value of the refractive index is 1, which corresponds to a vacuum. The refractive index of a medium is always greater than or equal to 1.
How is the refractive index of glass is to water is related with that of air is to water?
Each substance has an index of refraction. The index of refraction of water is about 1.3330 . The index of refraction of air at standard conditions is about 1.0003 . There is no such thing as the index of refraction of "water to air".
Is the refractive index of water wrt glass less or more than 1?
The refractive index of water with respect to glass is more than 1. This means that light travels faster in water than in glass, causing the light to bend when it passes from glass to water.
Discussion of reflactive index of glass and water?
The refractive index of glass is around 1.5, while the refractive index of water is around 1.33. This means that light travels faster in water than in glass. The difference in refractive index is why we observe light bending when it passes from air into glass or water, a phenomenon known as refraction.
Does water or air have the highest refraction index?
Actually we define refractive index with respect to a standard medium. Air has been taken as that standard. Hence refractive index of air is 1 and that of water is 1.33. But refractive index of water with respect to glass is 1.33/1.5 = 0.887 So, the answer is "water".
Does oil has the same refractive index as glass?
No, oil does not have the same refractive index as glass. Glass typically has a higher refractive index than most oils. This difference in refractive index is what causes light to bend or change direction when it passes from one medium (like oil) to another (like glass).
Why do things in a pool appear closer than they actually are?
The refractive index of air (n=1.00) is less than the refractive index of water (1.33) so when light rays transmit through the water the rays are refracted and produce a "virtual image" making the object appear closer.
Can light moves more slowly than air in the water?
Light in water is 1.333 times slower than light in the air. The reason is that the light is transformed into potential energy in the electrons and exits again as a light particle, so in air it performs the transformation less than in water. Air has a refractive index which is close to a vacuum, refractive index 1.000, whereas in water the refractive index is 1.333. The index is used when calculating the many different effects substances have on light. The index itself changes, depending on the wave length (ultraviolet, infrared, etc.)
