Question

Light wavelength and color

Ok.. Can someone check this?

The color of light is determined by its wavelength or frequency!?
I have read that the color of the light is determined by its wavelength.. so when light refracts, its wavelength changes that means technically its color should change (may not be apparent but m saying technically)

But I think the color depends on frequency.. I always thought the color is basically how many waves are hitting our retina per second.. so thats why as light refracts its color wouldn't change cause its frequency wouldn't change.! so which one is it?

Answer 1

@DLS @rajathsbhat @yrelhan4 @Jemurray3 @RnR

Answer 2

Color is determined by frequency.

Answer 3

i agree

Answer 4

Tho' one may say that it depends on wavelength as well, as frequency is related to wavelength by c=fλ.

But color is how rapid the photoreceptor on the retina receives the wave (or photons), so technically color is determined by frequency.

Answer 5

http://wiki.answers.com/Q/Does_thr_color_of_light_depends_upon_its_wavelength_or_frequency_fundamentally

Answer 6

but i'm confused now. http://www.scienceclarified.com/Ci-Co/Color.html :/

Answer 7

Well.....Most people probably would say that a light's color is always dependent on its wavelength. But this is true only if the light is moving through one medium, such as air. If the light enters another medium, such as glass, then the wavelength will change, even though the color will remain the same.

Rather, the color always is dependent upon the light's frequency, which is the number of waves of the light that pass a given plane in space per second (that is, the number of cycles per second). If the color of the light always was dependent upon its wavelength, then its color would change when it enters a medium with a different index of refraction. But it does not.

Answer 8

For For instance, if you observe a beach ball sitting near the edge of a swimming pool, then jump into the swimming pool and look up at the beach ball while your head is submerged under water, all the colors on the beach ball will appear the same as they did when you were standing in the air. What changes when light goes from one medium to another are both the speed of the light and the wavelength of the light. But the frequency of the series of light waves does not change; therefore, the color does not change.

Answer 9

The color change may not be apparent to us!.. we cannot detect the feeble changes that takes place in the wavelength!!

Answer 10

and come to think of it.. when you see things through a medium, the color IS AFFECTED :D.. isn't that right??? don't you see a difference in the shade of the color!?!?

Answer 11

well....let's say you and a friend are going swimming. Before you jump into the pool of water, you can see that he is wearing red swim trunks. If you jump in first, submerge yourself in the water, and look up at your friend still standing at the edge of the pool, the red color of his trunks will appear the same as they did before you jumped into the pool.

Next, he also will get into the pool. If you stand with your head above the water, you can look at his trunks that are below the surface of the water, and they will be the same red color. Finally, if you immerse yourself entirely in the water, you will perceive no variation in the red color of the trunks. In all four cases, the wavelength of the red light emitted from the swimsuit will change as the light passes into a different medium; however, the frequency of the red light always will remain the same.

Therefore, the color will remain constant as well, even though the wavelength changes when moving from one medium to another, since it is the frequency of the light that determines its color in all media.

Answer 12

@Koikkara don't you agree the color changes?!??

the shades look different.. take an object.. put it in water.. and see the color it would be different!!!

Answer 13

@Mashy ...wondering how can colour change....?

Answer 14

@Mashy .....Another example......

A simple way to test to see if the red color of an object appears the same in different media is to fill a glass with water and get a red straw. Notice how red the straw looks in the air. Place the straw on the other side of the glass of water and view it through the water and the glass; the color will not change. Then immerse the straw in the water and look at it from above, directly into the water, and then through the side of the glass. The redness of the straw will be the same, no matter how you view it, even though the wavelength of the red light is changing as it goes from one medium to another.

Answer 15

ok ok Koikara.. that doesn't matter.. cause when light enters our eyes its back in air.. so even if the color has changed INSIDE the water.. once the light comes out.. it ll be back to its original wavelength :P

Answer 16

I just looked into some papers.

Without going into very deep "biology", photoreceptor cells is triggered by the wavelength only.

The longer the wavelength, the longer it takes for the cell to absorb the photon, and hence producing different color perception.

So, changing medium will change the color.

Answer 17

The color of light is just it's frequency OR wavelength. It doesn't matter because they're interconnected. The point to be noted here is when light travels though a medium other than vacuum, it's speed decreases and is given by
\[c' =\frac{c}{n}\]
so in vacuum, \(c=f\lambda\) and in any other medium \(c'=f\lambda'\). The frequency doesn't change.
The color of light can be determined by either the frequency or the wavelength. And that color doesn't change because color is how rapid the photoreceptor on the retina receives the wave. And although the wavelength is smaller, the light also travels that much slower so that it produces the same flickering in our eyes.

Answer 18

And no, the color doesn't change.

Answer 19

I had thought photo receptor cells are triggered by waves per second? :-/.. ?!? and if you talk about photons.. then the energy of the photons is purely dependent on its frequency!!

Answer 20

@agostino....well, that means if u put an apple in water filled in a glass from outside when ulook u finds apple in orange colour?

Answer 21

@rajathsbhat
yea I am thinking the same.. its the frequency that matters.. and not the wavelenght.. but you are wrong to say that WAVELENGTH is connected to FREQUENCY.. they are not connected!!!

velocity is connected to wavelength.. and frequency is a constant which solely depends on the source!

Answer 22

If the wavelength is longer, the protein absorbs energy for a longer time.
@Koikkara You won't really notice tiny changes.

Answer 23

@Koikkara

NOO that will not happen.. try to understand when you look at that apple.. you are looking from AIR.. so the wavelength wil be back to normal!

Answer 24

as long as you know what medium you're dealing with, all three are interconneted.

Answer 25

No.. they are not CONNECTED thats wrong

frequency is a constant!!!...

its like F = ma..

a is not connected to m..!!

Answer 26

ok that sounds wrong

i mean M is not connectd to A :P

Answer 27

the acceleration obviously depends on the mass for a given force.

Answer 28

i corrected :P

Answer 29

So i think we all come to the conclusion thats its the frequency...

http://www.phy.ntnu.edu.tw/ntnujava/index.php?topic=1040.0

even the professor Fu Kwun Hwang... says the same ^_^

Answer 30

Before we have any more discussions, something needs to be clarified.

Color is a perception and it really depends on your retina.

Answer 31

@agostino
you may be right.. what color you see.. i may not see the same

but m talking about comparing the color change for the same person..!! :)

Answer 32

all three of them are connected as far as i'm concerned. If you know any two of them, you can find the third one. If that's not inter-connectivity, I don't know what is.

Answer 33

you can't say they are interconnected.. that would mean that frequency is DEPENDENT on velocity and wavelenght thats wrong

take example of waves on string.. the wave that i create.. i choose the frequency.. its how fast i oscillate it.. so frequency is MY choice.. the velocity and wavelength get decided based on various parameters like the tension, density and bla blah!!..

Answer 34

OF COURSE frequency is dependent on the velocity and wavelength. You can measure the wavelength and the velocity of light in any medium. You can THEN find the frequency of that light just based of the *definition* of frequency or time period

Answer 35

I am no expert in biology, but I believe without someone who knows photoreceptors very well, our approaches maybe a bit pointless.

Answer 36

yes you CAN calculate

similarly if you find the frequency of light and its wavelength in vacuum you can calculate its speed in vacuum

if you find the energy of a photon and its frequency you can find planck's constant

if you find the gravitational force between two masses, and their masses and the distance, you can find the value of G..

So does that mean these universal constants are DEPENDENT on those parameters??!??!?!?!

Answer 37

I sorta agree.

Answer 38

with @agostino, not you, mashy :P

Answer 39

@rajathsbhat
i m putting a final nail into your coffin.. FREQUENCY IS NOT A DEPENDENT QUANTITY!!!

Answer 40

your logic is highly flawed.. my previous argument tackles it!! and wins :D

Answer 41

wow that's an argument, huh? :P

Answer 42

We can both be right. It's just about how you view the world. It's not like measurements or scientific evidence can disprove any of our interpretations.

Answer 43

#nothingtodohere ^_^

Answer 44

http://i1.kym-cdn.com/entries/icons/original/000/006/707/nothing-to-do-here-template.jpg.scaled500.jpg :)

Answer 45

v=fλ may not be satisfied in some non-linear waves.

Answer 46

FREQUENCY IS INDEPENDENT OF WAVELENGTH OR VELOCITY!!!!!! done!!

Answer 47

make the endpoints of your measurement small enough and the equation holds no matter what, @agostino

Answer 48

raising your voice doesn't make you right, mashy :P

Answer 49

@rajathsbhat I view the wave from pure mathematics and there may exist non-linear wave beyond our assumptions.

Most of our basic assumptions can be shown in wave equation and it is not always the case.

Answer 50

i see...i'll just have to take your word on this one because i haven't started studying that kind of math.

Answer 51

I feel that we are drifting away from the original topic :P

Answer 52

i know.. i think original topic we all agree.. its the frequency that matters :D

Answer 53

We all? Not me. It's either the frequency or the wavelength. I don't care which.

Answer 54

:-/.. m not giving you medal :P

Answer 55

Gee, thanks.

Answer 56

k don't cry there you go :P

Answer 57

I don't know the precise reasoning but logic dictates color is due to light's frequency and not wavelength .

Answer 58

\[E = h \upsilon = hc/\lambda\]

Answer 59

@rajathsbhat The reasoning that was used above is right. Typically it doesn't matter but (at least classically) when light moves through a medium that's not vacuum, the wavelength changes with the velocity but the color stays the same -- so it's fundamentally a function of frequency, not wavelength.