# Tag Info

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A good experiment is Raman spectroscopy, it's quite simple, all you really need is a laser optical Goniometer with diffraction grating and sensor. The sensor could be the human eye if the room is very dark. Arduino and computing could be used to automate the detection and plot results.

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Working with significant digits is very prone to error, because it can be misleading. It is much better to work with explicit errors. So to rewrite your example with explicit errors: $\left(1.0 \pm 0.5\right) \times 10^3 + 1.00\pm0.05$ We now add the errors quadratically (assuming they are uncorrelated): $\sqrt{(0.5\times ... 0 Prime suspect is the switching power supply that generates the bias voltages for the tube. As the anode voltage is changed to increase the cathode current (the anode doesn't physically move), the power supply must work harder. Some switching power supplies operate at a fixed frequency, and so wouldn't display this behavior, but others have a variable ... 0 I appears that you are asking two questions. 1) what can generate a high pitch noise, & 2) why is the frequency of the noise directly proportional to the current applied? The general answer to 1) is, anything electromagnetic (inside or outside the vacuum tube) "loose," that resonates in the range of the mentioned frequency. The answer to 2) can only ... 0 You can answer your own question by running the experiment with the other two frequencies! If you obtain the same results, then the frequency does not matter. If the results are different, then it does. Actually, I am surprised that you are using AC, I think DC would be more appropriate. From the picture of the device, I see that it has red and black ... 0$1000$has an ambiguous number of significant digits. It could have 1, it could have 4. I think it is generally assumed that it has four unless otherwise stated. (For example, I've seen people put a line over the last significant digit, like this:$1\overline000$.) This is why scientific notation is useful. If you are saying that$1000$has$1$... 0 1000 has 4 significant digits as mentioned before, stating that the measured value is between 999.5 and 1000.5. 1.0 has 2 significant digits, staying it is measured within an accuracy of 0.05. Adding the numbers gives you a result within an accuracy of 0.5, so noting the result with 1 decimal digit is nonsense. If your measured value of 1000 indeed has only ... 4 The last digits in 1000 are absolutely significant, they state that you have not 1200, not even 1001 but exactly 1000. In scientific notation, you would write this as$1.000 \times 10^3$. Compare this to$1\times10^3$where you have just one significant digit. Update: consider the example from the question$1\times10^3+1.0$. The first term could be anything ... 0 http://typnet.net/Essays/EarthGrav.htm Here you go, explicitly calculated then graphed http://upload.wikimedia.org/wikipedia/commons/5/50/EarthGravityPREM.svg Earth's Mars-sized iron core is an outsized contributor to overall gravity, all the way down to its radius. 1 I can't tell what your equation means, but from your words "which part of our planet matters more in gravity, the core, or what's around it", you can define $$X=\frac{M_c}{M}=0.29$$ where$M_c$is the mass of the core and$M$is the mass of Earth, as obtained from this link. Since gravity from a spherical body with varying radial density is only dependent ... 0 When adding and subtracting, you can only go to the lowest number of decimal places. That is to say, we are dealing with precision and not significant figures when adding/subtracting numbers. If you have two measuring devices and one is accurate to 0.1mm and the other to 1mm, then you cannot definitively state the combined measure to 0.1mm, you can only ... 1 I think you don't need to worry about the effect of the ambient light assuming the source and detector you used are the same (or roughly the same) as in the specifications, and you used the non-standard strategy (i.e. setting the relative angle between the polarizers to be$\pi/4$) as described in the "Experiments" section the ambient light was not ... 3 As long as your ambient light is consistent and lower power than your experiment light source it shouldn't be a problem. As you rotate the angle of the polarisation filter you will eventually detect a peak at the detector--this angle will be different from the polarisation angle when the solenoid is turned off, indicating Faraday rotation. Like most optics ... 0 Short form: 1) Waffle with more and more of less and less as Yukawa potentials. 2) Do what everybody did to "explain" the Pioneer anomaly, the Fifth Force, absence of proton decay, and Gran Sasso's "superluminal" neutrinos: parameterize! There is nothing sacred about quantum gravitation or SUSY other than they employ vast numbers of people who cannot ... 0 If gravity is a fundamental force, then the Higgs mechanism is also. This is is true whether they are related or not. The Higgs mechanism is certainly the source of the inertial mass that inspired Newton to quantify what a force is, and how it behaves. Gravity, like the Higgs mechanism, can add mass/energy to matter in bulk (like constant acceleration), ... 0 You need to show some work. Draw a free body diagram. Then use Newton's laws with$\sum F=0$(since you don't want the child to move i.e. accelerate) in both the x and y directions and solve the two equations for the unknowns. There are three forces: friction, weight ($mg$), and normal force. 0 The oxygen rich condition will normally lead to a change in stoichiometry up to a certain degree. Thus, you will expect to have interstitial oxygen atoms possibly compensated by cation vacancies. -1 My previous answer was less comprehensive that what Charles Beaudette have well detailed. this books is available (courtesy of the author) on the site of University of Tsinghua http://iccf9.global.tsinghua.edu.cn/lenr%20home%20page/acrobat/BeaudetteCexcessheat.pdf Unlike the books of Huizenga and Taubes, it contains references to works done after 1989, it ... 0 (I presume you mean resolution.) In an SEM, the limit to resolution is almost always determined by the volume over which the electron beam interacts with the sample. If you shoot a beam into a sample at several keV, electrons will bounce around within a volume of something like a micron in size (depending on the exact voltage, the density and shape of the ... 2 Couder and Fort's experiment is based on a mathematical analogy between the Hilbert space of a particle moving in two dimensions, and the two surface of a vibrating oil bath, which interacts with an oil droplet bouncing on top of it. Naïvely, one might try to extend this analogy a two-particle system by having two oil droplets bouncing on a single ... 0 You can assume that acceleration is constant during the intervals. Then you can compute the velocities and distances as in your formulas using these changing acceleration values for each interval.$V_i=V_{i-1}+a_i*\Delta t_is_i = s_{i-1} + V_i \Delta t_i+a_i (\Delta t_i)^2/2$something like this 0 I'm not sure I understand exactly what your question is. In order to use the kinematic equation for some distance, time, etc. the object has to be moving under constant acceleration. If you really aren't looking at a situation involving constant acceleration I would approach the problem with conservation of energy laws. 1 Firstly, if your waveguide is a hollow conductor, it cannot support TEM modes. There must be at least two separate (electrically insulated from one another) conductors in the waveguide's cross section for TEM modes to propagate. The reason is that the transverse field dependence of a TEM mode is the same as that of a static field, as I explain in detail in ... 0 I found a solution to my problem using the vertical displacement: $$$$\tag{2} h_d = d_1 tan(\theta) + \frac{d_2 tan(\theta)}{n} + d_3 tan(\theta)$$$$ solved for$\theta$this becomes $$$$\tag{3} \theta = \arctan \left( \frac{h_d}{d_1 + d_3 + \frac{d_2}{n}} \right)$$$$ 5 Given your description, you clearly have non-exponential behaviour. However, there are two possible reasons for this behaviour: Some materials in the system are nonlinear and do not follow Newton's law of cooling, which is that the heat flux at a given point is proportional to the temperature gradient vector. I should think this is the least likely of the ... 6 The real issue is that the cup wasn't really full so that adding anything more would make it spill. You can clearly see the the level slowly growing above the top of the cup, as would be expected due to surface tension. Eventually another coin finally exceeded the limit, and a little water spilled. There is really nothing extraordinary going on here. ... 0 Edit: regarding your core question: no, if you drop a coin into a glass filled 'more' than the brim-level, such that any more water will cause it to spill, water will spill out. But, instead of a coin, if you insert something that has other properties that allow it to absorb water whilst not suffering any volumetric changes and has strong cohesive force ... 0 The effect of CRs on electronics will increase with time. As the electronics shrink, we will be fitting more bits per unit area. As such, there will be less charge necessary to define a bit (how many electrons or holes signal that a bit is 1 or 0). Since one CR event will deposit a given amount of charge, the probability that a bit will flip (or the number ... 2 To address the actual question of how we know the composition of UHECR without relying on source information (of which we have none), we have to look at their extensive air showers (EAS). After an UHECR hits the top of the atmosphere an EAS is created in the air, but p and Fe will create EAS with different shapes. Properties of hadronic interactions are ... 3 Measuring dead-time (or other hardware efficiencies) is a non-trivial proposition, and there is no completely general solution. The answer that John gives in the comments ($\tau \times \text{number of events}$) is the best case: a system with few interconnections and no "extensible" contributions to the dead time. "Extensible" describes a system where ... 0 First of all what is magnetism. Maxwell says that: $$\nabla \cdot \vec B = 0$$ Where$\vec B$is the magnetic field. This says that the divergence ($\nabla \cdot\$) of the magnetic field is zero. Which means that you can visualise a magnetic field as a large tank of fluid (lets say water) permeating all of space. This "water" can flow but not expand or ...

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Rotation and Translation The distinction is crucial for understanding Newton’s mechanics. In broad terms, translation indicates motion in a straight line; and rotation indicates motion around an axis. When Newton muses in Principia that maybe there is no such thing as a body truly at rest, he is also implying that maybe there is no such thing as motion in ...

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KISS. Have a tall ship cruise toward shore from 50 or more miles out. The crow's nest appears then down the masts to the ship's deck. Calibrate mast length vs. distance and you have an empirical measure of curvature at sea level. The math, entry below, is explicit.

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The curvature of the Earth is not enough to really 'curve' any object that's city-sized or smaller. The reason for this is that the radius of the Earth is really big.[citation needed] To make this more precise, say you make your chair one metre wide, and you have the edges pointing towards the centre of the Earth. You can then form an isosceles triangle ...

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"The difference between theory and practice is that, in theory, there's no difference, but in practice, there is." At Colorado State University over the past several years, students using the Teachspin muon lifetime apparatus have been consistently getting muon lifetimes that are slightly but significantly too short. In late 2012 I spent several months ...

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Your worry is not necessary. In the usual experiment the detector measures the distribution of the time between the muon stopping in the detector and the time of it's decay. Then an exponential curve is fit to the data and the lifetime taken from the fit parameters Muon decay is a processes analogous to radioactive decay, and (like all exponential ...

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http://www.amazon.com/s/ref=nb_sb_noss_1?url=search-alias%3Dindustrial&field-keywords=mercury&rh=n%3A16310091%2Ck%3Amercury is an excellent source (the one I was talking about above)

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He used what is called a torsion balance. His experimental method is outlined very nicely in this video. After Coulomb published the result of his work, however, it was debated as to whether his experiment really did provide enough evidence to support his claim that the force between two point charges really did follow the equation we now call Coulomb's ...

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The only happy footnote to a meson accelerator is relativistic time dilation. If you can beep it to a few nines of lightspeed within a lab frame microsecond, you've got a presumed linear accelerator, http://en.wikipedia.org/wiki/File:FrischSmith.svg "Results of the Frisch-Smith experiment, confirming time dilation by measuring the decay rate of muons in ...

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Disprove string theory by empirically falsifying a string theory postulate. No postulate can be defended or it need not be postulated. Falsify BRST invariance and string theories collapse. Falsify the Equivalence Principle (EP) and the whole of physics needs a rewrite. No measurable observable violates the EP. All continuous and most approximately ...

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Before addressing the question directly, it should be helpful to sketch some relevant relations involving the notions timelike curve and light cone of an event (and here at first also distinguishing its "past" or "future" parts): Considering the light cone of one particular event, and an (open) timelike curve containing another identified event inside the ...

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With the setup you describe I would expect to get 60% without too much effort. Optimizing the mode matching to the fiber as described by @jayann should get you up to 80%. An experienced person could do all of this in a day, but if you are new to alignment of optics then it will take longer. If you are only getting 30%, then either your fiber is bad or ...

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When you are using APC facet of your receiving fiber, you should set a proper angle for that fiber due to misaligment between laser beam (it can be considered to be plane wave) and the fiber. Once you realign the APC fiber with a small angle (let's say 8 degree) then attach to the laser beam path, you will increase the coupling efficency.

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What do you mean by "the waves radiate like a cone"? Anyhow, you will have reflections from the the metal pieces all around and that will be received to some extent and interfere with your measurements. if you don't want that happen then cover the metal with absorbing material. Check out how an "anechoic chamber" is constructed. Note that a dipole be it ...

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Time is perceived threw moving objects, changes and things transitioning from order to disorder (positive entropy). But time itself is a dimensional axis much like length, height and width. "but as far as the discussion on entropy" it is dynamically highly improbable and could mean harnessing all the energy in the universe in order to reverse it. "but then, ...

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People defined time as a variable going forward long before entropy was defined. Biological/consciousness time, which you also discuss, forced the concept of time and a way /unit to measure it, as cultivation and buildings forced a concept of space and units to measure it. The celestial clock of sun moon and planets was used even by primitive people. ...

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Feynman proposed that antimatter is the same as matter, except travelling backwards through time. Let's assume that this is true. If the Big Bang created antimatter, then it would have travelled off in the opposite temporal direction, into Negative Time. So we won't be seeing it again. Any antimatter we might see in our Universe was probably created locally, ...

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Re your question 1, have a look at my answer to Conversion of mass and energy. You might also want to look at What keeps mass from turning into energy?, which is related. These give a basic desciption of how the energy of motion can turn into particles of matter like top quarks. Re questions 2 and 3: the discovery of the top quark was made at the Tevatron ...

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There are a couple of main sources of intrinsic error (that is, not associated with counting photons from your source) which CCD's have. The first is as you have already mentioned called read noise. Here is a reasonable definition of read noise (taken from Romanishin's free pdf on Photometry): After an integration (exposure), the CCD must be read out to ...

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One of the simplest measurements you can do is to characterize the spatial mode coming out of the laser. This can be done with a simple photodiode and a scanning slit (optical chopper or razor blade mounted on a movable stage). I wrote a brief note on making such a measurement here. This isn't the most interesting of measurements if you aren't going to ...

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