My question is why light must bend when it goes from one medium to another. Say if it goes from air to water. Water is optically denser than air, which means that water slows down light more than air does. So why doesn't the light just slow down in water, why does it have to bend in the process?
2007-12-02 01:23:01 · 5 answers · asked by Ebony 1 in Science & Mathematics ➔ Physics
Light is an electromagnetic wave. The speed of its propagation depends on two material specific constants electric permittivity e and magnetic permeability u.
c=1/sqrt(e u) [1]
The change of electromagnetic properties of material causes the propagation vector to change direction and that is manifested as refraction[2]. The speed of propagation is related to the index of refraction and the speed of light in vacuum as
n=c/v[3]
2007-12-02 01:45:20 · answer #1 · answered by Edward 7 · 0⤊ 2⤋
The speed DOES change at the boundary. If the medium is more optically dense, the speed reduces. The frequency remains the same, so this means the wavelength reduces too.
A wave travels in a direction perpendicular to a front on which all points are momentarily in phase. In other words, imagine drawing a line through all the peaks of the sine wave at an instant. The wave is travelling perpendicular to this line.
When the wavelength changes, this direction must adjust to keep the peaks in phase. If the wave hits the boundary perpendicular then no change is needed. Otherwise some parts of the wave hit the boundary before others, and the only way for the front to stay in phase is for the direction of travel to change.
In other words, interference rules out waves in any other direction.
2007-12-02 09:51:09 · answer #2 · answered by Anonymous · 2⤊ 1⤋
the process is called refraction. the light bends because there is a change of density. the density of water si about 90 times bigger than the density of air. light can't slow down because it's propagation speed is a universal constant, it doesn't depend on the environment
2007-12-02 09:31:31 · answer #3 · answered by pure_bliss27 2 · 0⤊ 2⤋
It is due to the change in velocity and wavelength , light undergoes a change in direction when it passes through two different medium.
2007-12-02 09:39:15 · answer #4 · answered by Venkat R 6 · 0⤊ 3⤋
edwards answer is interesting.
and correct as i understand it,
2007-12-02 10:17:05 · answer #5 · answered by brownian_dogma 4 · 0⤊ 1⤋