Invisibility of flint glass rod in carbon disulfide

In summary, when a rod of flint glass is immersed in carbon disulfide, it becomes almost invisible because both substances have the same refractive index. This means that there is no reflection at the glass surface and the light passes through as if there is no boundary between the two substances. To understand this phenomenon, one must have knowledge of the Fresnel equations which describe how reflection and transmission occur at the boundary between two media. These equations take into account the difference in refractive index, angle of incidence, and polarization. For more information on the Fresnel equations, one can refer to the provided link.
  • #1
Amith2006
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# A rod of flint glass when immersed in carbon disulfide becomes almost invisible. It is said that it is because both have same refractive index. What I don’t understand is just because they both have same refractive index, why does it become invisible?
 
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  • #2
How can you see a glass block submerged in water? What effects do you observe?
 
  • #3
Amith2006 said:
# A rod of flint glass when immersed in carbon disulfide becomes almost invisible. It is said that it is because both have same refractive index. What I don’t understand is just because they both have same refractive index, why does it become invisible?
Is there any reflection at the glass surface if both substances have the same index of refraction? If it is otherwise transparent, how would you detect the presence of the glass using only light?

AM
 
  • #4
To appreciate how reflection and transmission occur at the boundary between two media requires an understanding of the Fresnel equations which are derived from Maxwell's equations for electromagnetic fields. It turns out that the reflection and transmission coefficients depend on the difference in refractive index of the two media*: the bigger the difference, the greater the reflection. With matching indices, the reflection is zero... everything gets transmitted, just like there was no boundary at all.

*They also depend on the angle of incidence and the polarization. For a start, go here: http://hyperphysics.phy-astr.gsu.edu/hbase/phyopt/freseq.html#c1
 

1. What is the scientific explanation for the invisibility of a flint glass rod in carbon disulfide?

The invisibility of a flint glass rod in carbon disulfide is due to the difference in refractive indices between the two substances. Carbon disulfide has a higher refractive index than flint glass, causing light to bend around the glass rod and making it appear invisible.

2. Why is carbon disulfide commonly used in experiments involving invisibility of objects?

Carbon disulfide has a high refractive index and is optically clear, making it an ideal substance for experiments involving the bending of light and the concept of invisibility. It is also relatively easy to obtain and work with in a laboratory setting.

3. Can other substances besides carbon disulfide make objects appear invisible?

Yes, other substances with high refractive indices can also cause objects to appear invisible. For example, liquids such as glycerin, oils, and certain types of glass can produce a similar effect. However, the specific refractive indices of these substances may vary and may not be as effective as carbon disulfide.

4. Is the invisibility of a flint glass rod in carbon disulfide permanent?

No, the invisibility of the glass rod in carbon disulfide is temporary and depends on the angle at which light is entering and leaving the substances. If the angle is changed, the glass rod will become visible again. Additionally, if the substances are mixed or stirred, the invisibility effect may be disrupted.

5. Are there any real-world applications for the concept of invisibility in carbon disulfide?

While the concept of invisibility in carbon disulfide is primarily used in scientific experiments and demonstrations, it has potential applications in fields such as optics, camouflage, and cloaking technology. However, more research and development is needed to fully utilize this concept in practical applications.

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