It is well known that light travels slower through water. If it could exit the other side as with a transparent tank, does it speed up again and if so where does the energy come from to accelerate it ?
2007-04-02 11:03:53 · 10 answers · asked by Anonymous in Science & Mathematics ➔ Physics
Yes, it does. When light enteres any substance, including air, it slows down. When it is no longer traveling through the material, it resumes traveling at the original speed.
It is not that it is accelerating, it is more like not having the obstacles. The energy has always been there. Just that when it has to travel through dense materials, more of it is used up to go through the material.
By the way, the fact light slows down when traveling through material is the basis of why lenses work. It IS a scientific truth.
2007-04-02 11:13:35 · answer #1 · answered by tkquestion 7 · 2⤊ 0⤋
it does travel slower in water. The speed of light is actually 299 792 458 m / s, but this is only in a vacuum. In any other material is slows down. In air it is every so slightly slower at 299 702 547 m/s.
The speed of light in any material = 299 792 458 / refractive index of that material.
Refractive index of diamond is about 2.54 (this varies according to the quality of diamond) so the speed of light in diamond is only a mere 118 028 527 m/s!
It doesn't require any energy to speed up again... just think of a car driving through mud and then moving onto tarmac. Then car speeds up because it gets more grip.
It's similar for light, it's speed is slowed because the electric field (light consists of an electric and magnetic field) creates a disturbance in the charges of atoms in the material. When it leaves the material it causes no disturbance and can speed up again.
The energy of the light has nothing to do with its speed. The energy is proportional to the frequency.... which does not change.
2007-04-02 18:07:16 · answer #2 · answered by Anonymous · 2⤊ 0⤋
Yes, it does speed up again. It never really lost any energy, so none is needed to get it up to speed at the back end of the tank. The energy of light is a function of its frequency, not its apparent speed (as is the kinetic energy of an object with mass).
2007-04-02 18:08:51 · answer #3 · answered by Anonymous · 1⤊ 0⤋
Light refracts, dissipates, and is not attracted to itself again, so the linear light passing through an object is not accelerated or, for that matter, theoretically slowed. It simple remains constant at its energy's entrance and exit speed. Intensity is affected; speed is relative.
2007-04-03 06:09:24 · answer #4 · answered by colorcanuck 1 · 0⤊ 0⤋
the speed of light = 299 792 458 m / s, but no if it is slowed down it will not speed back up. Energy can not be created or destroyed and thus once the energy is lost it will not re-accelerate after exiting the water.
2007-04-02 18:08:16 · answer #5 · answered by Wojo 1 · 0⤊ 4⤋
This question is based on a fallacy:< It is well known that light travels slower through water>. How does light travel slower through water? This is a better scientic question, which is not open to speculation.
2007-04-02 18:08:42 · answer #6 · answered by Ke Xu Long 4 · 1⤊ 3⤋
Not likely unless something speeds it up
2007-04-02 18:07:30 · answer #7 · answered by Unknown 5 · 0⤊ 3⤋
I didn't know its slower in water. hmmm. I don't know. That's a really good question
2007-04-02 18:08:30 · answer #8 · answered by I want u2 hit me as hardas u can 2 · 0⤊ 3⤋
It does not speed up at all
2007-04-02 18:10:12 · answer #9 · answered by V.T.Venkataram 7 · 0⤊ 4⤋
300000km/s
2007-04-02 18:06:09 · answer #10 · answered by ninja_1215 1 · 0⤊ 2⤋