Colour Definition and 173 Threads

Please don't beat me for bringing some dumb puffed-up internet meme to PF. Seriously, this is embarrassing. But fascinating. (I'm posting this in biology because I'm certain it is a colour perception issue.) Maybe you have seen this by now. http://digg.com/2015/what-color-is-this-dress I...

How the Mean colour of visible spectrum is yellow? Shouldn't that be green according to acronym VIBGYOR?

Hi, If you were to half Earth's orbit around a K4.5V main sequence star (assuming the same composition and density of atmosphere), what colour would the sky be? Thanks in advance. Chinspinner

We see an object coloured because of the component of light reflected by it. But what is in the object that makes other wavelengths absorbed by it and one to reflect.

Hi, new member here, I know very little about physics so have no idea if this is a very basic question or not, but I was wondering if anyone knows the answer to the following: Does there exist a type of plastic or glass that (whilst remaining completely see through) can allow the user to see...

What is the explicit 3x3 matrix operator which measures the colour of a quark? Essentially what I want to know is what is the analogue of ##S^z## for the measuring of spin.

I imagine it depends on the chemical makeup of their atmospheres.

Hello I am going to study Electrical Engineering this coming semester and i just wanted to make sure that i don't get any problems due to my minor red-green colour blindness. I have no problem distinguishing between resistor codes but i normally flunk tests for colour blindness. I rarely...

What would happen if the double slit experiment were to be undertaken using white light, and one of the slits was covered by a monochromatic filter (i.e. something which only one wavelength could pass through), and apart from this there was no detector monitoring which slit each photon was...

So for my assignment I have to calculate the wavelength given an angle, colour, 100 slits/mm diffraction rating but no frequency. Angle = 3.4 degrees Colour = Purple For v =∫λ, I need the wavelength or frequency to work out anything, v is the speed of light. But I cannot see how to find this...

First, let me see if my facts are straight. White coloured objects reflect more light of ALL frequencies than black coloured objects, including infrared, etc. Hence a white coloured object is cooler than a black coloured object. If visible light was the only factor, a blue room would be cooler...

Hey. I am wondering how can blue and green colour planes exist in a photo, when I am using red bandpass filter while taking photos? Red bandpass filter let's only red light through. But when i analyze the photo, green and blue planes are still there. How can it be? Thanks in advance

Hi, I'm a recent high school graduate and I was just wondering about where colour comes from. I know about the flame tests of different metals and that the sky is blue due to refraction and stuff, but what about just everyday objects? Is wood brown because the electrons in the wood particles (I...

Homework Statement Here is quite challenging problem from Enderton's popular textbook A Mathematical Introduction to Logic. "In 1977 it was proved that every planar map can be colored with four colors. Of course, the definition of "map" requires that there be only finitely many countries...

Hi, could anyone tell me please, what would be the best colour to paint a boat to keep the cabin cool in a tropical climate? I think the answer probably is white because it will absorb less radiation, but I'm not sure because of course it will also emit radiation better as well. Any...

This isn't really a homework question but it's from a past paper for revision. It is a short question so it shouldn't require lengthy mathematics. It asks you to show that a quark and an anti-quark of the same colour will attract. The problem gives the 8 generator matrices of SU(3) and...

I am working on an automotive project and am looking to pick up any gains that I can. In doing so, I've been studying the effect that colour has on thermodynamic characteristics. To be specific, I am interested in finding: A) What colour(s) will help retain the most heat i.e. minimize thermal...

Seems a bit odd why colour determines if it is absorved or not, doesn't it? My teacher could not answer this question.

Hey, I'm having an issue seeing how these octet states are reproduced via SU(3) transformations, in my notes it is written: "Now, the remaining 8 states in (25) mix into each other under SU(3) transformations. For example just interchange two labels such as R<->B and you'll see these mix"...

Homework Statement a) calculate the energy, in joules, of a quantum of light with a wavelength of 590 nm. b)will this colour be able to produce photoelectrons from the surface of a metal with a work function of 3.0 eV? Explain your reasoning. Homework Equations f=c/λ E=fh ek=hf-W The Attempt...

Hi everyone, my question is: what information can someone get by just looking at the colour of a plasma? I the elements inside the chambers, together with some(few) common impurities. Using the common spontaneous emission formula i can guess what transition emitted light with a particular...

Suppose I have a picture of a flame, or some other blackish-body like emitter, and I can see that the RGB value of a part of the flame is [106, 216, 177]. How would I go about determining the temperature of this? I'm sure you'd use Wien's law etc, but I can't see how to get from the RGB value...

I know that CuSO4 is blue or PbI is yellow. Is there any way to remember the colour of all chemicals?

I was wondering today what is the colour of pure neutrons confined together, I'd guess it's either completely black or white, because it doesn't have the electric orbitals needed to generate different wavelengths. I'm generally guessing it just reflects light and is therefore what... maybe a...

We are looking to produce a spray changes colour when it comes into contact with Carbon Dioxide. Ideally this would be colourless when sprayed, but become a visible "smoke" where carbon dioxide is present. Failing this, we are open to a white "smoke" that changes to coloured where Co2 is...

Hi, I know without light, an object can't give out radiations thus, show no colour. So if we keep any object in a completely dark room, it would not exhibit colour. Suppose we send in a large amount of sound energy into the same room. The object in the room would absorb some amount of...

Homework Statement a certain young's apparatus has slits 0.12 mm apart. the screen is at a distance of 0.80 m. the third bright line to one side of the centre in the resulting interference pattern is displaced 9.0mm from the central line. calculate the wavelength of the light used. What...

Why is the colour of sea water blue?

Hello, I've recently been trying to find out what colour the sun is, but I've had no luck. If you take a look at this picture: http://apollo.lsc.vsc.edu/classes/met130/notes/chapter2/plank_e_sun.html You can see that the maximum wavelength is in the green section. If so, shouldn't we see the...

Homework Statement This is just my doubt and not really a question. We know that speed of light changes upon change in medium of propagation. Its wavelength also changes. But its frequency doesn't change. So, does the colour of light change upon change in the medium of propagation...

We know that the wavelength of visible light changes when it travels between two media with different refractive indices. Here's my question: does light change colour when it moves from air into glass? I had quite an interesting but inconclusive discussion about this with my Physics teacher...

The sun appears yellow because is made of white light and blue,green,indigo gets scattered.My question is why the planets and the moon appear white with their case the same thing should happen and even they should appear yellow.

A bag contains a total of 50 balls (10 red, 10 blue, 10 green, 10 black, 10 white). If I draw x balls from the bag, what is the probability that the largest number of balls that are the same color is y? For example, if I draw 7 balls, and I get 4 Blue, 2 Green, 1 Red, y=4 It'd be nice if you...

If you heat inox steel in presence of air, up to a specific temperature, you get a yellow colour of the metal surface; increasing the temperature it becomes red; still increasing, blue. Is it due to the formation of oxide layers of different thickness? Which effect is responsible of the colour?

[Solved] How and why does a prism split white light into the colour spectrum Homework Statement How and why does a prism split white light into the colour spectrum? Homework Equations Red light has a lower frequency than violet light. As speed of light = wavelength * frequency, red...

Dear members, Soaps and Shampoos comes in various colours, but their lather always appear white. What is the reason for this phenomenon?

why sky is blue in colour?? why sky is blue in colour??

Hello there. I was reading something on the affect sodium hydroxide has on ordinary starch from plain flour. I read that sodium hydroxide can change the physical and chemical properties of starch. I conducted an experiment where I mixed 2mol and 8mol sodium hydorxide with plain flour in a test...

Homework Statement If a surface which glows red hot at 500C , calculate the approximte temperature at which it glows white hot, explaining your reasoning Homework Equations I have no idea . The Attempt at a Solution Must b something to do relating wavelength and temperature ...

At last someone has made a point of broadcasting that colour is in your head and not wavelength. The recent BBC Horizon programme on TV, whilst being a bit fanciful and touchy feely, made it quite clear that the colour we see / appreciate is affected by many factors and totally depends on the...

is that true that the colour of sky is blue or is it just the reflection of sea water

A picture that seems to show up a lot in high school physics is one like this: http://www.kollewin.com/EX/09-15-03/electromagnetic-spectrum.jpg There's the wide range of electromagnetic waves at different frequencies, of which we can only see a narrow band. My question is, why do red and...

I have read in my class 10th book and other books that black(usually dark) colour is avoided in summers and this is the reason why impure ice melts quickly . I am wondering why ?

I didn't know where to put this so I thought this was mabye the best place. I was told I am "red-green" colour blind. Then I was told that I might find science difficult because I might not be able to read litmus paper, tell the difference between chemicals etc. Yet I can easily tell the...

I am familiar with the ideas of colour subtraction and addition, such as adding blue and yellow to make green. However, how does this work from an electromagnetic standpoint? Is there basis for the addition or subtraction, or averages, of the wavelengths or frequencies? Is the colour change a...

I'm asked to examine a set of processes and determine if they are possible/impossible according to the Standard Model. So I have to check that energy, baryon number, color, lepton number, quark flavor and the symmetries are conserved. I'm fine with all of these but how do you go about checking...

Hey guys Today I've done an experiment and I found that when different color of light from the same light source (put of different color filter on the same light source) shine on a beaker of water, the temperature of the water will rise. And different light will rise the temp of water in...

I've been told that the structure of Cu Nitrate is that of a octrahedral and appears similar to the picture attached. also that the distance at which the two verticle orbitals are away from each other varries the intensity of the blue colour, with the further the orbitals being away from each...

From what I know, different metal ions produce different colours. This is due to the fact that electrons jump to the next energy level when energy is absorbed but then released some of that energy back, producing different wavelengths and thus different colours. What I want to know is...

OK, I've looked for about two hours now and can't find what I want (though I've found lots of stuff that doesn't do what I want.) Years ago, Para Paints had a widget on their site that would have you choose one of about 32 colours, and would then give you a palette that matched it. There's...