Physics Help Forum Question about refraction

 Light and Optics Light and Optics Physics Help Forum

Feb 17th 2009, 06:29 AM   #11
Member

Join Date: Dec 2008
Posts: 65
[quote=hey jude;3408]
 Originally Posted by ryansuchocki Why does the first sittuation occur, and not the second?[due to change in speed.(due to refractive index) so the waves bend towards normal and since wavefront has to be perpendicular so situation 2 occurs. i hope this answers the querry ]
The pictures are the same physically. But the white lines are supposed to be wave fronts. That means the line (or plane) of all points that are in phase. In the bottom picture they are not wave fronts. The points along the lines are not in phase. (you know that for a spherical wave the wave fronts are not straight lines). So the white lines in the bottom pictures does not mean anything.
Try to apply Huygens's principle to a case where there is no change in speed (reflection, for example) to get a better understanding of how it works.

Mar 6th 2009, 03:05 AM   #12
Junior Member

Join Date: Mar 2009
Posts: 1

 Originally Posted by ryansuchocki Hello, I've been searching for an answer to this question for hours, and no-one else seems ever to have asked it. So, if anyone could help that would be great... I understand the analogy of refraction involving a car driving, obliquely, across the boundary between two terrains - and that the difference in 'propagation' speeds affects the direction of the car - but i don't see how the car is a valid representation for a beam of light. The car 'bends' across the boundary because its particles are bonded together. If one of its sides slows down, the other side is inclined to remain attached - but what keeps the components of a light beam connected? What makes the wave front 'want' to remain a line? What stops one division of the front (possibly photons?) from speeding ahead (or falling behind) the divisions which have not yet reached the boundary? Thanks in advance...
Light has two character, particle(photon) and wave. You can't see it in both form in the same time. Refraction is a phenomena that only could be explained by wave character.

 Tags question, refraction

 Thread Tools Display Modes Linear Mode

 Similar Physics Forum Discussions Thread Thread Starter Forum Replies Last Post Germanlongstrike Light and Optics 13 Apr 24th 2017 01:06 AM Aruj Light and Optics 4 Feb 17th 2011 12:43 PM DarkSoul Light and Optics 2 Dec 26th 2010 06:22 PM {smile} Waves and Sound 2 Aug 19th 2009 08:44 PM Air Light and Optics 3 May 13th 2008 05:12 AM