raf Posted May 31, 2008 Share Posted May 31, 2008 need some clarity does light travel in a straight line? does it bend with different mediums? is light speed constant through different mediums or does ir slow down? what changes the wave length of light as red has the longest and purple the shortest? when you answer are they the same when light is exposed to gravity (except black holes)? Link to comment Share on other sites More sharing options...
ecoli Posted May 31, 2008 Share Posted May 31, 2008 (edited) need some clarity does light travel in a straight line? yes, until it hits something does it bend with different mediums? If it hits something or passes through a field, it can bend is light speed constant through different mediums or does ir slow down? speed changed depending on the medium what changes the wave length of light as red has the longest and purple the shortest? Depends in what sense... are you talking about the diffraction or white light or a shift in the wavelength from red to purple? Edited May 31, 2008 by swansont fix quote tag Link to comment Share on other sites More sharing options...
Klaynos Posted May 31, 2008 Share Posted May 31, 2008 need some clarity does light travel in a straight line? Yes, although if spacetime is curved the light will follow the path of curved spacetime. does it bend with different mediums? No, individual photons do not bend but are absorbed and re-emitted with slightly different direction. is light speed constant through different mediums or does ir slow down? Photons all move at the same speed, but because they get absorbed and re-emitted that takes some time and the apparent speed is different. what changes the wave length of light as red has the longest and purple the shortest? The energy of the photon. So it depends how the photon is created. when you answer are they the same when light is exposed to gravity (except black holes)? Black holes are not special. Light follows curved spacetime which is caused by gravity. Link to comment Share on other sites More sharing options...
raf Posted May 31, 2008 Author Share Posted May 31, 2008 Black holes are not special. Light follows curved spacetime which is caused by gravity. will gravity affect the speed of the photons therefore increase the time to arrive at a destination? The energy of the photon. So it depends how the photon is created. do different wavelengths like PURPLE and RED get to a destination faster than the other as one has more wavelength than the other and how does it change from one too the other(process and conditions) Link to comment Share on other sites More sharing options...
Klaynos Posted May 31, 2008 Share Posted May 31, 2008 No it will no affect their speed, but it will change their direction. The speed of light in a vacuum is constant for all wavelengths. Although I see to recall there being some astrophysical evidence that there might be a very very slight difference, but the cause is unknown, so the speed of light in a vacuum is constant to the best of our knowledge. Purple and red are relatively close, 400nm and 700nm, when compared to the complete spectrum. http://www.antonine-education.co.uk/physics_gcse/Unit_1/Topic_5/em_spectrum.jpg Link to comment Share on other sites More sharing options...
raf Posted June 2, 2008 Author Share Posted June 2, 2008 does gravity effect time (say near large objects but does not effect the speed of light) Yes, although if spacetime is curved the light will follow the path of curved spacetime so if it follows the curve it would not Necessarily go in a straight line so it should take longer to get its desitnation???? Link to comment Share on other sites More sharing options...
swansont Posted June 2, 2008 Share Posted June 2, 2008 does gravity effect time (say near large objects but does not effect the speed of light) Yes, although if spacetime is curved the light will follow the path of curved spacetime so if it follows the curve it would not Necessarily go in a straight line so it should take longer to get its desitnation???? Yes. This is known as the Shapiro delay. The reason for the delay, AFAIK, depends on which frame of reference you use. One way of looking at it is a longer path due to the curvature of space. Link to comment Share on other sites More sharing options...
raf Posted June 2, 2008 Author Share Posted June 2, 2008 what relation does wavelength have to the human eye that we percieve the colour of it and would there be any relevance to time when it changes from one wavelength to another. Link to comment Share on other sites More sharing options...
Klaynos Posted June 2, 2008 Share Posted June 2, 2008 The human eye has 3 types of colour detector. These have detection spectra associated with them, and each has a different peak detection. The brain interprets the relative intensities detected by each of the detectors and works out a colour. It's why you can create lots of different apparent colours with just 3 colours... Link to comment Share on other sites More sharing options...
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