How does light or photons pass through glass?

Question

it has two properties wave and also matter
it gains mass as it gains speed but has no mass when at rest
maybe the wave nature can pass thru it
but how can a body having mass actually penetrate through a solid glass

Answer 1

Matter isn't really solid, as researchers working with alpha particles found in the early 20th century.



But you've got two misconceptions here:

1.  Photons have no rest mass. They are pure energy.  A high-energy muon may zip through glass with a very low probability of being stopped, but photons can't interact via any of the nuclear forces.

2.  The reason visible photons can go through glass is because glass's electrons are tightly bound.  It takes more energy than the photon has to kick an electron to a higher open energy state, so the absorption doesn't happen.  If you change the photon wavelength (soda glass gets opaque in both the far infrared and UV) or the composition of the glass (obsidian instead of quartz), you'll see photons absorbed rather than transmitted.



U V:  Light slows down in glass because the electron density increases the permittivity ε to a value considerably greater than the free-space value, ε0.  The speed of light in free space is determined by the magnetic and electric permittivity:  c = 1/sqrt(ε0 μ0).  If you increase ε (which can be dependent upon the photon energy!), the speed of EM radiation decreases.

Answer 2

[Engineer...] if there is no absorbtion.. how do you explain the speed of light slowing down in glass???



[qin].... you have a few misunderstandings about light.

1. Light has 2 natures... but can only show 1 at any one time... it's EITHER a wave OR a particle.... NEVER BOTH.,,



2. we don't know what MASS it has... we say that it has ZERO rest mass as to comply with Einstein's equation of Mass increase at high speeds. As we speed up.. anything with mass (no matter how small) will 'gain' mass.. when we get to the speed of light.. our mass will be INFINITE... but hang on... Light travels at the speed of light... so if it's REST mass is ZERO... well ZERO x infinity is... still ZERO... so Einstein's equation holds true..... So LIGHT's mass is 'mathematically' ZERO..at all times....



Now to answer your question... [Engineer] is almost right... but.. glass's molecules, and electron orbits are structured is such a way, that when a photon hits an electron, and boosts it up to a higher level... that electron jumps back down, and emits another photon that has the SAME property as the original photon that hit it in the first place... that is, same energy, same angle.... So that it appears that the light passed through unobstructed.



The time that electron took to jump up (absorbing the photon), and fall back down (emitting the photon)... is the 'delay' time of light travelling through glass.... you see.. when the photon jumps from one electron (in one molecule) to the next electron (in another molecule)... it's travelling at 'c'.... the fact that light 'slows' down in glass (and other media).. is due to this 'delay' time.. of the electron absorbing and re-emitting the photon.



Hope this has helped.

Answer 3

Light/photons travel as waves. Glass is made of many many molecules that seem to be solid but consists of atoms with a nucleus and orbiting electrons. There is a great deal of space between the nucleus and the electrons, which have a very small mass and are moving. A high percentage of the photons can weave in between the molecules in the glass and pass through the other side. The longer the wavelength of light, the further it can penetrate, because its wave oscillation is much wider allowing it to find a gap in what it is hitting and pass through. Photons are virtually massless.

Answer 4

uh...no.

it has two properties wave and PARTICLE properties, not mass. in fact, photons do not have mass. your second line does not apply to a photon because mass as presently defined is the "energy of an object at rest", and a photon when existing is never at rest, it always moves at the speed of light when in empty space. it only "slows down" once it's inside a transparent material as it passes through. and as it comes out, it's back to c.



think of them as quantized energy, little packets of energy and not actual objects that pass through another object. (think sound)



of course, light/photons are governed by relativity and quantum mechanics and it's a common mistake for one to be unable to shake the classical, Newtonian approach to viewing these things. but um, yeah. hope i helped clear that up a bit.

Answer 5

hi Gaurav, permit me strengthen your query a splash. Why is something sparkling? whilst gentle encounters a textile, it may go together with it in distinctive distinctive techniques. those interactions rely on the character of the gentle (its wavelength, frequency, capacity and so on.) and the character of the textile (how heavily packed its atoms or molecules are, no remember if those atoms or molecules are ordered, no remember if the electron orbitals are spaced such that they take up gentle of specific frequencies etc). case in point, gentle falling onto a leaf encounters various pigment molecules, predominantly chlorophyll. those molecules take up gentle from the pink and blue ends of the seen spectrum. the the rest gentle is scattered back as a results of fact molecules in a leaf are particularly tightly packed and so we see a eco-friendly leaf. whilst gentle falls onto a block of metallic, it encounters atoms that are tightly packed in a usual lattice and a "sea" of electrons shifting between the atoms. particularly some the gentle is scattered back from this type of cloth, it rather is why we see a astounding metallic floor. Glass is often pronounced as a liquid, yet rather it has properties of the two a sturdy (its molecules do no longer circulate very plenty) and a liquid (the molecules are no longer arranged in any style of ordered way). Molecules in glass are no longer packed right into a good lattice and except tinted, it would not comprise molecules that seize gentle with a definite capacity. So whilst gentle encounters glass, maximum of it passes directly via. subsequently, this is obvious. desire this helped answer your query, Shama