推翻v=frequency*wavelength (20分)

I think you have a fundamental misunderstanding with the wave speed equation.

Yes, light travel at different speed in different medium.
However, all color of light travels at the same speed in the same medium. (eg. Red and Blue light both travel at speed X1 in medium 1. Red and Blue light both travel at speed X2 in medium 2.)

That's right "v = speed = constant" in that equation.

Therefore, by defining the frequency of the particular color of light, you are also defining its wavelength.

It is good that you think deep and raise up this question, often people don't ask even they come across a dilemma like this and they stuck with the wrong concept for their whole life and accepting what is given. In fact, this fundamental 'speed of light is constant' concept is what trigger Einstein's investigation of relativity theory!

Keep asking question, you should be happy to know where went wrong in your thinking instead of disappointed about being incorrect! This bring you one step closer to the truth.

2009-03-29 13:44:08 補充：
In addition, refractive index has nothing to do with speed of light. Again, the key is "speed of light of all wavelength is the same while traveling in the same medium".

2009-03-29 13:44:13 補充：
For your interest, visible spectrum (red, orange, yellow, green, blue, violet) travels at the same speed as other invisible spectrum (x-ray, gamma, microwave, radiowave).

http://en.wikipedia.org/wiki/Speed_of_light
(see the first paragraph)

2009-03-29 13:47:25 補充：
If you still don't understand, here it is...

v = f * lamda
v = constant

f = lamda * (constant)

Therefore, one f correspond to one lamda!

I don't really realise what do u mean by "By dispersion of white light inside a prism, we would find out that the speed of red light is faster than that of white light, so it also has higher refractive index", as white light is the effect of combining the visible colors of light in equal proportions, that is to say, it consists of red light. If you don't believe me, you can check it out from relevant books or otherwise.

Yeah, your concept is nearly entirely correct. "The longer the wavelength of light, the greater the velocity of it " is correct in most of the cases; however, it is not correct when light is travelling in a vacuum. Waves can be "blocked" by air or other matters, affecting their velocity.
(http://www.bun.kyoto-u.ac.jp/~suchii/EonFizeau.html)
(http://users.net.yu/~mrp/chapter14.html)

"v=frequency*wavelength " is actually applied when considering lights in space. In schools, just like we always neglect the air resistance when calculating mechanics questions, the small error in the velocity of light is overlooked as well.

Hence, I don't agree with u at all.

2009-03-28 21:13:33 補充：
公式指定是要用在在真空的EMwave才会100%correct
你總不能把圓形area條公式用來計正方形的and say loudly" this area formula is not correct"吧?
in most of the cases, calculations are never exactly correct. but it's okay as we just want to take a reference.

2009-03-28 21:15:41 補充：
如果v=frequency*wavelength 錯, 很多公式皆錯
如果你推

2009-03-28 21:18:34 補充：
wait a minute, "公式指定是要用在在真空的EMwave才会100%correct" should changed to "公式指定是要用在在真空的EMwave才会99.9%correct"因為c的實際量值至今亦未有人計出

2009-03-28 22:20:25 補充：
take it as a reference

2009-03-28 22:24:34 補充：
from which you can know "Why does light propagate more slowly through a material environment than through a vacuum?" i'm not gonna explain it here as it's too complicate.

2009-03-28 22:39:36 補充：
如要搏最佳答案應討好作者才对,而非「狂插」作者
anyway, just figure out who is correct

2009-03-29 12:25:32 補充：
just like the velocity of a free falling object can be affected by air resistance
but the law cannot be overturned