When Is Light Absorbed By Something? What Happens After That?


5 Answers

Adedeji Kenny Oluremi Profile
The reflection of that light shines on the other side of the object.
Mihai Ogasanu Profile
Mihai Ogasanu answered
Everything converts in the universe. SO light converts into something else / or a number of things once it hits an object. Like a leaf from a tree - converts in: Provides photosynthesis - reflects the green wavelength - and provides heat. When you tan in the sun - same thing - produces heat + modifying skin pigment (tanning) + reflects your skin color. Same with everything.
Now you may think of a black t-shirt - how come it reflects black - as black is not light so it's what ?! Well, what you might perceive as black - is just a wavelength reflected by the "black" t-shirt. Wavelength that our eyes cannot see - so it seems black . You don't see a tv's remote control IR LED - but a video camera can! Right? IR or UV. Etc...
So, light has a constant speed - but it's formed by all these wavelengths - different frequencies - are they the same speed? - no - so how come?! Approaching galaxies glow blue and those going away glow red - like a doppler effect. Hmm mm... That definitely makes you wonder if light's speed is a constant and cannot be slowed down or increased - knowing all those effects - and wavelenghts . What happens after the light is absorbed, well that's  a really good question. It seems such a waste of energy - imagine how quick light can provide power to charge a battery from a solar generator / panel. And that happens instantaneously. So I admit it seems so strange what happens with the light when you turn it off in the room and all goes dark suddenly. As if it passes through things, or maybe reflecting all those colors/wavelengths from the things around us is what it does. So we can see :) Light is not matter. But we can see matter with our eyes.:) Light seems to be part of what we are. Vibration. Wavelenghts. Colours. Time. Present. Future. Past. Far or Distant. And none of all these important things are matter. So what is matter?


Naveed Akhtar Profile
Naveed Akhtar answered
When light is absorbed by something (e.g. metals) it increases the kinetic energy of the molecules of the material. This is due to the fact that light is also a form of energy and comprises atoms. When they strike another surface they transfer their kinetic energy to the molecules of the receiving medium. When the kinetic energy of the receiving medium increases, the vibratory motion of the molecules of the material also increase. Hence the temperature of the material increases as a result.

This phenomenon is true to a greater effect in case of metals, as the arrangement of molecules is in ordered form in them. There are spaces in between molecules to allow for vibration. However, in case of non-metals such as wood, the molecules are not in ordered form and have little space to vibrate. Hence wood is not heated considerably in sun. In case of clear objects which are transparent, such as glass, the light passes through and only a small portion is absorbed. Hence glass heats up to a lesser extent in sun.
thanked the writer.
J commented
@ mnabpk ...

You have got it all wrong ....

This is due to the fact that light is also a form of energy and comprises atoms. [/QUOTE}

If Energy were comprised of atoms as you try to suggest, how could light travel through space (space = a vacuum = a total lack of atoms) ?

When energy is transmitted through atoms it is called "conduction" ;-)

FYI Molecules are made of atoms

I suggest you go and learn some basic science ;-)

HTH ;-)
Anonymous commented
Yeah a bit wrong.
Light is just energy. Although it has mass when moving, as demonstrated in compton scattering, it has no mass when stationary and so can not be described as matter.
b a Profile
b a answered
Light is a form of energy. When light strucks a thing. There is a flow of energy from light energy to heat energy(which is transformed) in a materials surface. Energies do not disappear, but are transformed from one energy to another energy form. E.g. Heat energy to mechanical energy, like the steam generator ^^
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Naveed Akhtar
Naveed Akhtar commented
Light travels in the form of electromagnetic waves which can travel through space. As the kinetic energy of the molecules of metals (some) increases above certain level they start emitting electromagnetic waves of light. This is the principle of an electric bulb. Heat is felt due to the increase in kinetic energy. Regards naveed

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