studiot

But it doesn't, as I have tried to explain. You are mixing up situations. The way to see the colour of additive light sources is to shine them on a common area on a white screen or paper. You don't stare into the beam. What you then see in your two different situations looks different because it is different. That is because the illuminated spot you see is giving off two different lights. One is the pure narrow bandwidth called yellow. The other is the agglomerate of all the other light in the beam, which is what I meant when I originally asked how much grey there is in the left hand sample.

I like it. +1 @thoughtfuhk The beginning of the tile presupposes there is only one purpose? Why can't lots of different 'purposes' be served at the same time. Perhaps 'evolution' tries out lots of different possible progressions at once, some bear fruit, some do not (there is a biblical parable about this) But perhaps all those trials are just in case or are just like a drug manufacturer haveiong a row of test tubes with (slight) variations on a theme.

I suggest you restudy the difference between additive and subtractive colour systems. Since we have been dicussing the colour of light in this thread we are discussing the additive colour system, whereby you sart with no light (black) and add light of various colours, each time changing the result colour until you have added light of all colours when you get the white (or the near white broad spectrum (not necessarily continuous that is a different thing) of your halogen lamp. This is how colour projectors work. The alternative is the subtractive system where you start with white and remove particular colours either by filtering or by reflecting from a coloured object that removes the desired colour. The end result of this is of course, no light or black. This is how mixing paint colours works. http://www.worqx.com/color/color_systems.htm

You made claims fundamentally opposed to conventional thinking about tides. Please respond to my comments as required by the rules of this forum instead of listing the names of some water bodies in the northern hemisphere. I would agree that mathematically a tidal wave is also called a soliton, but as I pointed out there is more than one mechanism of generation for these in hydraulic bodies.

I don't think so. (Issue underlined). What do you think might be the physical mechanism for this to happen?

Einstein was not a world class Mathematician, although no one surpassed his standing in Physics. His liflong friend Grossman helped with much of the maths. Willian Clifford , on the other hand, was one of the leading Mathematicians of his day ( a differential geometer to be precise just like our own ajb) and made many advances in his field. Clifford algebras are named after hime and concern differential forms, the exterior calculus and stuff, which is only these days coming into its own in Physics and Engineering. He, in his turn relied heavily on the pioneering work and insights of Riemann whos efamous Doctoral lecture kicked the whole thing off. Gauss before hime had some insight, but didn't publish it all so we don't know how much he knew, but he was responsible for the original work on the geometric curvature of curves. Poincare added his own theoretical work including the famous Poincare Conjecture, only recently proved by Perelman, in non-Euclidian geometry and the Poincare disk, which is one way to contain 'infinity'.

Did you read the Konica-Minolta document I linked to? It really is an excellent presentation. And it offers 'official' answers to your questions plus some that you haven't asked but need to.

It wasn't Poincare anyway. Strange is correct they all did their bit, from Gauss to Riemann to Clifford I have emboldened the relevant phrase.

The point to remember is that the Uncertainty Principle refers to any determination of the values concerned. This includes, but is not limited to, direct measurement, deduction from other data, calculation of the physical variables involved. Possibly the simplest way to understand this is to follow the reasoning behing the broadening of a spectral emission line. Such reasoning is used all the time in Spectroscopy.

Indeed they are and it is 20 years+ since I threw out my (then) old university notes on Environmental Engineering including illumination. I have been trying to think of a simple one paragraph explanation of the role of grey. Hasan, it is good to have someone interested in the subject, especially as the last persion wanting to 'discuss' colour perception was a troll. So here goes. Illimination and the visual perception of illuminated object a very complicated subject because of the interaction between the the source, the light itself and the illuminated objects. This is not helped by the fact that the relationships change with the intensity (and sometimes other parameters such as direction) of the illuminating light. So first off there are standards to refer to. One of these is the CIE 'Standard Sky' https://www.google.co.uk/search?q=CIE+standard+sky&ie=utf-8&oe=utf-8&client=firefox-b&gfe_rd=cr&dcr=0&ei=aIbEWpesJo-Btgfb56fIBQ When we (or a recording machine such as a camera) view an illuminated object we see two separate aspects of the incident light. We see the level or intensity as a measurement we call the Luminance and The perceived colour or Chrominance. These are not independent and at very low levels of light we can only see the Luminance. That is we cannot see colour. The Luminance property by itself allows us to create a monchrome or greyscale model of the image, point by point. This is how early fax machines, photocopiers, the silver screen at the cinema and old fashioned 'black and white' television work. The luminance is a simple single numerical value that specifies the light density. The chrominance is much more complicated and is not a single value but has to be represented by a collection of several numbers that indentify it on a two or three dimensional chart. This is further complicated by the fact that there are several different charts schemes available and each includes a different overall range of the light spectrum, known as the (colour) gamut. So some colours appear in one scheme but not in others. But having chosen the scheme it does not end there because we see with two eyes and each of our eyes sees a slightly different colour emanating from each point on the object in view. This is because the light is affected by shading and other effects from nearby points and perhaps also from the light source itself. Amazingly our brain is able to filter out these differences and assemble a coherent unique colour value for any point on the illuminated object. Here is a good semi technical introduction to the subject. https://www.konicaminolta.eu/fileadmin/content/eu/Measuring_Instruments/4_Learning_Centre/C_A/PRECISE_COLOR_COMMUNICATION/pcc_english_13.pdf

No because the appearance of brightness depends upon the response curve of the eye. The point I am trying to make is that pure colour (monochromatic light) has a very narrow band, perhaps even narrowere than your 570-590 nm. Grey is a mixture of certain proportions of all the primary coulours (I forget the proportions but they could be looked up). Grey is also regarded as the universal neutral colour.

I'm quite sure the " Institute of Geography of the Russian Academy of Sciences. " can do much better than this. I'm also sure it can get its terminology correct. Russia is, after all, one of the two nations on Earth that attempts to produce charts of the entire World Ocean. So Terminology. You need to distinguish between 'currents', which always flow one way and are part of the basic thermally driven movement of water in the world ocean. and 'tidal streams' which are the horizontal movements of water due to tidal action. Unlike currents, tidal streams reverse once or twice a day. Are 'Tidal waves' proper terminology? Do you mean a Tsunami, born of tectonic activity or a hydraulic jump like the Severn Bore, born of rapidly changing bottom gradient?

Did you miss my question or did you not understand it? There clearly is a difference between narrow band light and wideband light, which includes some of the original narrow band. Further the statement "this is also aceptable.... etc" makes no sense. So please restate you question and premise.

Don't the colours on the left have added grey?

Good morning and welcome. You will need to be more specific as to your requirements. Here is a recent report with data, standards to compare against to follow. https://www.epa.ie/researchandeducation/research/researchpublications/researchreports/EPA RR 183 Essentra_web.pdf

Yes exactly V = IR is the problem. If you plot a graph of voltage against current (or better the other way round) the above relationship is a straight line through the origin, so beloved of schoolboy Physics "Please Miss I got a straight line through the origin for my practical" These are known as transfer curves and, like the rest of more advanced Physics life is never that simple. The simplest step up is of course "what if it's affine?" That is V = IR + C, but still a straight line? In fact the ratio R = V/I is the slope of this graph at any point and the inverse ratio (called the conductance) is perhaps better used and we have that current is some function of applied voltage, I = f(V). We can then do calculus on this. JimS should remember something called transconductance, appropriate to valve (tube) circuitry and FET circuitry these days. For a junction transistor, the function f(V) is too complicated to write as an equation so electronic manufacturers publish graphs showing families curves for their products. Next up the transfer curve ladder comes what statisticians call the Gompertz curve or the S or Z shaped curve which allows switching activity to be created in a circuit. Then we have devices with negative resistance regions such as tunnel diodes (available in the 1960s) that have more that one solution for the equation. This allows the creation of oscillator circuits vibrating back and fore between the available states represented by alternative solutions. It can also lead to circuits with chaotic behaviour. I mentioned oscillators, which introduces other variables - time or frequency. Temperature is another one. Ohm's law is an idealisation, just as the Gas Laws, but we abstract ideal transfer curves for all the more complicated situations. Ohm's Law then becomes just the simplest possible idealisation in the form V = IR. But in the form R = V/I it can be used to define resistance as the limit of ratio of the voltage to the current at a point.

Are you referring to the fact that it is possible for R to vary with the current, or are you referring to possible circuits where V = IR does not hold? I assume your question refers to the underlined statement? Let me first observe that even with the simple devices the OP is starting with, he can have voltage without current. Having current without voltage is more difficult, but possible. As to the 1960s, that is when the quad NAND gate integrated circuit was introduced. This houses four identical 3 terminal circuits that can sink/source an output current up to a specified maximum at the voltage logic level for binary 1 or 0, when presented with suitable logic level inputs. Simplified the rules are To pull an input low you must apply between 0.0 and +0.8 volts sinking current of aout 1.5milli amps to zero. To pull the input high you must apply a voltage between +2.0 and +5.0 supplying a current of 40micro amps to the positive rail. The output can source or sink ten current times these values at an output voltage of +2.4 volts. This is nothing like Ohm's Law. But it was the start of modern digital electronics. Ohdearme, I see you replied whilst I was composing the above. The switches can be used with LEDs and current limiting resistors to play with study digital electronics easily. I also use them to look at series and parallel circuits and other things. You can get 10 simple switches for £1 on Ebay. The (tiny torch bulbs) filament lamps do not need the limiting resistors that is the only reason I suggested them. The important thing about Ohm's Law is knowing when you can use it and when you can't, which would come out in the projects I was offering. You would indeed use it to calculate the size of current limiting resistors

Sensei you are right, LEDs have become more efficient. This only highlights further the need for current limiting resistors. Also I think your equations for power are a more useful starting point than Ohm's Law. People are more interested in the energy / power and efficiency of electrical devices than materials properties such as conductivity/resistivity, to start with.

I am wondering if Maxim's grasp is weaker in English than Physics. He is trying to get a grip on the Physics and seems to grasp clear statements on the subject, but doesn't seem to me to be always expressing exactly what he means. (A PM in French might help him) So attacking poorly worded English as poor thinking is counterproductive. The rocket was not mine.

Because he has an accelerometer that measures the force created by the acceleration. Perhaps you would like to comment on the highlighted paragraph?

As I'm sure you are aware, the SN7400 was one of the original digital logic gate chips and as such the inputs and outputs definitely do not obey Ohm's law. There are many circuit components which do not obey Ohm's law here are some recent examples at SF No one has said that Ohm's Law doesn't have it's place. But it can be (and IMHO usually is) introduced too early into the study of electrical phenomena. Yes indeed so why don't you help the OP with some useful circuits, from your lifetime of electronics experience, as requested instead of squabbling with me? I am going to start that now carrying on where ohdearme left off last time someone tried to push Ohm's Law onto him. Hello again ohdearme, I note you have some LEDs. Plus some resistors. So to start let use these us look into current limiting resistors. Current limiting resistors are essential components in many, if not most, circuits. If they are connected the right way round, standard LEDs will show a light output with a current from 0.01 to 0.1 amps. So if you connect your 9 volt battery to an LED through a 1000 ohm resistor and then 100 ohm resistor you should see a difference in brightness. You should try both a 1.5 volt and a 9v volt battery and try both the resistor and the LED each way round and note what happens in each case. If you can try also two and/ or three 1.5 volt batteries to see what happens. Here is a thread to help you get several 1.5 volt batteries stacked up correctly. If you can get hold of a bunch of cheap (on/off) switches and some old fashioned filament light bulbs it would be good for another time. I realise that folks looking into electrical matters are interested in how their toothbrush/vacuum cleaner/cooker/heater/doorbell/radio/cooker/loudspeaker.... works and most importantly, how to safely connect and use them and this will be aimed at that, if you want to continue?

So?

Sorry communication difficulty I think. The rocketmaster = pilot so is automatically in the rocket frame.

So let us see your explanation of the working of an SN7400 using Ohm's Law. Or perhaps you could treat us to the application of OL to a 9 volt PP3 battery?

No, not really. The formulae v2 = u2 +2fs, and v = u +ft is taught to high school pupils who study kinematics of constant acceleration. When the constant refers to the velocity we have the simpler formulae v = u and s = ut. Maxim, since you say you have some higher Mathematics you should be able to cope easily with this modern book on University Mechanics which covers Relativity in the second half with really clear explanations and working. Dynamics and Relativity W D McComb Oxford University Press Here is a sample page on relativistic acceleration