why an open window is considered as an perfect absorber? i want sceintific answer relating to physics?
961817
Above answer is quite to the point.. i would just like to add that, if u consider a light ray entering a open window there is very less chance that it will escape out again. in short it can be assumed to be absorbed.  \n\nIn the black body radiation, we need a perfect radiator n perfect absorber.
724946
it absorbs light energy aka the photons and bounces them around and releases electrons
470750
Ernie... I love this question..  it rocks.\n\nThe answer, however, is going to be just a little dissappointing.\n\nAs I'm sure you know, all light is both a particle and a wave; it is a form of nearly pure energy.  As we know from theoretical physics, energy can never be created, nor can it be destroyed.  It just changes forms.  According to the third law of thermodynamics, energy always goes from higher to lower forms when left on its own, the lowest form of energy often being considered to be heat.  And that's where your wandering, amazing laserlight goes, it turns to heat.  \n\nWhy?\n\nBecause your room of mirrors is completely imperfect.  Your mirrors are dismally inefficient reflectors of light, and the room is full of air.  Household mirrors actually reflect less than 25% of the light energy that shines on them back to you.  Lab quality mirrors made for laser work are, I believe, in the high 80% to low 90% reflectivity efficiency range.  Every time your beam hits a mirror surface and bounces off, it looses more of its energy to heat..  just as it does as it passes thrugh every atom and molicule that makes up the air in the room as well.  Your laser might make it one or two 'miles' of beam length in the room before it is bouncing around.. which would make for thousands of beams.  But, since light travels at 186,000 miles per second, your two mile beam lasts 1/93,000th of a second after you turn the power off before it's gone.  So, it DOES keep going.. but not long enough for you to percieve it.\n\nSo, IF you had perfect mirrors, IN a perfect sphere (remember; you couldn't have any corners!) a COMPLETE vacium inside it with NO particles of dust of ANY kind, and a way to fire the beam into the amazing sphere without leaving any void for energy to escape...  your theory would work, if all that were PERFECT.  But; the biggest catch would be; you could never know if it were working!  Because to find out; you would have to have a void in the sphere to see or measure it...  and measuring any energy source draws energy from it.. so, there goes your light again.\n\nSo, that's why, but it's still a great question.  Theoretical Physics is full of stuff like that...  and thinking about it will turn your brain into silly putty for days.  Keep 'em coming, Ernie..  you've got a great future if you keep your mind working like that.
125793
basic principles of wave propigation. a body in motion tends to stay in motion. if what you're saying is the vacuum is deviod of all matter, including subatomic particles, the wave would continue forever, with one exception. if the beam reflecting around the room collided with itself (say it caught itself in a corner), it would cause sufficient refraction to scatter the beam eventually. photons expend no energy to travel, so the room would stay lit up forever. and man, that would have to be some badass 100% reflective material! ;->
1103995
mirrors attract ligtning due to their glass. Particles in the glass contain small amouns of parfanenon. This element is conductable with ligtning like water.
639214
See this article for an explanation:\n\nhttp://webtips.dan.info/new-window.html
146531
This site is constructed well and has a high level of detail (up to degree level).\n\n\nhttp://hyperphysics.phy-astr.gsu.edu/hbase/hframe.html
97822
i think sound energy can pass through a medium so should pass through opaque object. light energy is not transmitted through opaque objects only transparent objects so it will be reflected at the boundary. Degree of reflection would depend on the opaqueness of the object
372946
Actually, If you shine light on a steel door, the atoms that make up the surface of the door will absorb the photonic energy, and if they absorb enough photonic energy, they will emit the energy. Sometimes the newly emitted energy is outward away from the door, and sometimes the energy is emitted inward and propagated to atoms further into the doors structure.\n\nTo make thing more complicated, the energy is only emitted as photonic energy sometimes, when the atoms have the right amount of energy built up to release a quanta of photonic value. Other times the energy is emitted as heat energy. \n\nThe door is trying to propagate the photonic anergy through to the other side, however the atoms that comprise the door are capable of retaining a great deal of energy, and when they do release it, based on quantum mechanics, there is only a probability that it will be directed into and not out of the door.\n\nIf you quickly heat the atoms in a specific region ,(fill them up with energy), without giving them time to transfer the energy away, (blow torch) you can see the glowing red door on the other side.\n\nIn short, it is due the the energy retention strength of the atoms that make up the solid.
46903
Although a lens can intensify sunlight (and even start a fire), what window glass normally does is act like a filter. It admits visible light, which is then reradiated as a mixture of visible and infrared light. The infrared light is blocked by the glass and trapped inside the building or car, warming it. \n\nThis is of course the well-known greenhouse effect. That is why cars can get so hot in the sun that they can be lethal to babies and pets inside. That is why the earth is habitable, because greenhouse gases in the atmosphere act like glass and keep the earth warmer than it would otherwise be. The greenhouse effect is what allows the cultivation of fruits in colder climates (another name for greenhouse is hothouse).
481372
nothing. even the vacuum of space has energy flowing through it. So, in theory, a perfect vacuum is nothing.
639495
Anything is visible beacuse either light emitted from it, or light reflected from it reaches our eyes. If light passes through something completely, it will not be reflected to our eyes, and the object will become transparent or invisible. Glass comes very near this.
163803
when the windows are rolled up the air in the car isn't moving as fast as the air outside the car. the air is moving as it would if the car were perfectly still almost
12898
When white light (for example sun light) strikes a black object, almost all the light (all visible wavelengths) are absorbe and not re-released.  That is why a black object heats up more under the sun than a white object that reflects all visible wavelengths.  You can still see the black object because it may not be perfectly black and not all visible wavelengths are absorbed or because some of the white light is reflected at the surface without being absorbed.  For light to be absorbed, the photons must penetrate the material and interact with the electrons of the atoms and molecules it meets which absorbs either none, some or all of the photons before reflecting the rest back to your eye as black, a specific color or white light.  Also consider clear glass where the photons interact with electrons and are almost all allowed to pass through only slowing down because of the longer path - permitting lenses and magnification.
1164989
The energy from the light is absorbed into the walls, etc.  If you could create a room that had everything in it 100% reflective, then the light would continue to exist.  But, you wouldn't know this, because you are not 100% reflective, and you would absorb the light.
1136153
many materials absorb better at the infrared wavelengths than the shorter wavelengths so the absorbed energy is conserved as heat.  There are materials that absorb shorter wavelengths and convert the energy to heat, such as a microwave oven???  Water absorbs at that frequency (1-2 GHz) and the water molecule resonates.  The vibrational energy is re-emitted as heat due to a Stokes shift.\n\nThe shorter wavelengths are more energetic and more capable of depositing energy that might show up as heat but it depends on the absorption of the material itself.
146601
Gee, I dunno.  I use windows for fenestration.  I like the sound of the birds chirping outside on a sunny morning.