Measurement Definition and 1000 Threads

(This a new thread as proposed by Borek post #2349) Neutrons and neutron "beams" are very hard to detect with portable instruments. The most common portable instruments are gas proportional counters using thermal neutron capture in BF3 (boron tri-fluoride) or He3 gas. Proportional counters...

Say we have two particles with angular momentum basis states |j_1~m_1\rangle and |j_2~m_2\rangle and the combined system is in the state: |0~0\rangle=\sqrt{\frac{1}{6}}\left(|1~1\rangle |1~-1\rangle+|1~-1\rangle |1~1\rangle\right) What is the probability that measurements of the...

I've been looking at the level measurement data from the Fukushima plants during the accident, and wondering if the somewhat suspicious behaviour is due to clogging of the impulse tubes ore some other malfunction, or if the measurement is arranged in such a way that it does not measure the core...

Never do we change a completely imagined, clearly defined linear measure. We don't change the fahrenheit scale as we use temperature measurements. Humidity, radioactivity, velocity, weight- None of these are ever manipulated. I hope this helps to make a point. Why does it automatically make...

Hi there when doing an experiment with my university associated with my university related to a simple pendulum, I was not confident when calculating the error there was in my measurement, the relevant equation is: T=2\pi\sqrt{\frac{L}{g}} where T=period L=length of pendulum and g=accel...

Hi, I would like to measure the signal noise in a tv cable after introducing a splitter and compare it with the original signal. Keeping in mind the bandwidth frequency of the tv cable signal transmission, what kind of instrument do I need? Oscilloscope perhaps? At what speed? I don't know...

Two doubts... 1. Consider two frames S and M, the latter moving at constant velocity v wrt S. I know that it's possible to synchronize clocks at different positions in a particular frame. But is it possible to synchronize a clock in S and another in M, and if so, how to do it? 2. Suppose...

Temperature measurement can be categorize into...how many ? Temperature measurement by mechanical effect.. Temperature measurement by electrical effect.. Temperature measurement by radiation.. am i right ?

I’m asked to do efficiency measurements on washing machines, collecting several parameters including water-intake. For this I need real-time data with 0.1 liter accuracy. Just now we use three SCAMPY water flow meters (two for cold and one for hot water), manufactured by the French company...

Here's a quote from Einstein's 1905 paper regarding evaluation of times of events occurring at places remote from the observer : Please explain the meaning of that last sentence. I mean, where and why does the disadvantage of using the above method arise?

first of all, I'm a new bie of QM, with q1,p1 and q2,p2 the couples of position and momentum THE QUESTION IS: can I just measure a \hat{q1} with no measure of \hat{q2}? and how? and how I calculate the new wave function with the dependece of q2? I hope that \hat{q1}|q1,q2>=q1|q1,q2> is...

I need to design a scale. It is a simple 2-D problem. All you need to know is that it's a plate on a vertical spring. Each end of the plate slides a little ways into an indent. It is a scale for weighing ingredients in a bakery. A weight of 22lbs (+or- .25 lbs) is acceptable. If there isn't...

Hey, I am working in a lab and I simply can't figure out a method to measure the pressure between two plates I'm compressing. Here's my set up: I have a metal plate with perpendicular screws attached to another metal plate (I will be putting my sample between these plates). All I do is...

What is the best way to measure the voltage from a high resistance circuit? The circuit resistance is higher than the resistance of the voltmeter.

Can anyone help me with our investigative project in physics? This is just a very simple project. Our experiment is all about the effect of salt on the rate at which a glass thermometer measure a sudden change in the temperature of a solution. The thermometer will first be allowed to be at...

Hello everyone, The students of our college wants to start a club for measurement. We were thinking that our college should give more opportunities for our students to be creative with the methods of physics and so, the idea of this club arose. We will take contact with one of our donators, but...

how to measure porosity, porosity factor and void factor of a solid mixture?

How to measure density as much precise as possible. Possibly with a waterproof balance under watter. What the prices are?

Homework Statement hello, I have ten results of measurements, all are identical, and how i can count error? it is this: L = ( 20 \pm 0,1 ) cm and all errors, mean squared error etc are 0, how can I count this now?

If we measure a quantity with 2 different tools(once by direct measurements and the other time through simulation), is it true if we compare these 2 results together by using paired t test? Does it makes sense ? For example we want to measure the aborbed dose of a patient, so once we measure...

In school we somehow measured the minimum and maximum wavelength our eyes could see Unfortunately, all I remember is that we were looking through a slit between jaws of some sort of calipers and used a ruler to do measurements Can anyone please give me an insight of how to set up such...

<Pic> This is the theory of ammeter give in a book. please read it. Now, my question is that coil will only respond to the current through it i.e. i1. But this is a very small part of total current (Rc >> r). Does this mean that all the moving coil ammeters show wrong current? Please...

Mass, Charge, Spin has definite properties before measurement. What else aside from position, momentum that have NO definite properties before measurement. Is it only position and momentum?

Add One "Dollop" Hello; I have tried to be as accurate as possible with my measurements while cooking and I have done fine so far, but what exactly is one 'dollop'? I have been told to add one 'dollop' of mayonnaise and I have no idea what this means. I am assuming it is not a small...

Homework Statement This is an extension to problem 4.55 in Griffiths. The problem is: The electron in a hydrogen atom occupies the combined spin and position state: \lvert \psi \rangle = R_{21} \left(\sqrt{1/3} Y_1^0 \chi_+ + \sqrt{2/3} Y_1^1 \chi_-\right) a) If S_z is measured, what...

When electrons are passed through a double slit and can either display a wave-like interference pattern or a particle-like build-up pattern, is that because their momentum/direction is changed by the measuring device interacting with them, or due to some other feature associated with being...

I just watched a show on Einstein concerning this theory of general relativity. Around 1922 photographs of stars from an eclipse were used to measure the bending of light from those stars around the gravitational field of the sun. Those measurements were used to confirm Einstein's theory. All...

As we all know, the current should be measured in series with the multimeter... However, how do we connect the multimeter in series with home appliance without damaging the wire(plug)??

I am interested in how PSD (particle size distribution) affects the transmittance of a material and I am trying to find an accurate process to measure it so that I can test and gather data on how it affects it. I don't know if transmittance is the proper word for what i want to study, but all...

How do you do a Bell measurement on a state that doesn't have a power of 2 number of qubits? I've got GHZ states like this: |GHZ_{ijk}> = \frac{|0_{i}0_{j}0_{k}> + |1_{i}1_{j}1_{k}>}{\sqrt{2}} And I'm trying to Bell measure the following state at qubits 2 and 3...

Question: Among six measurement of the boiling point of a silicon compound, the size of the error was 0.07,0.03,0.14,0.08 and 0.03 degree Celsius. Assuming that these data can be looked upon as a random sample from the population given by f(x;\theta) = 2(\theta-x)/\theta for 0<x<\theta =0...

Doppler shift of light shows distant galaxies moving away from us at high speed. This of course has been taken to prove that the universe itself is expanding and it has been theorized that the expansion is accelerating. To actually empirically measure and prove the theorized acceleration...

Hi, [c=speed of light] if a particle travels at a velocity x/t and momentum p, such that (c-x/t) < (delta-x)*(delta-p) (ie the Heisenberg limit), how could one tell whether what one was looking at was a photon traveling at speed c or a particle traveling indeterminately CLOSE to c? also...

Homework Statement An initial state is given: {\lvert {\psi(0)} \rangle} = \frac{1}{{\sqrt{3}}} \left( {\lvert {100} \rangle} + {\lvert {210} \rangle} + {\lvert {211} \rangle}\right) An L_z measurement is performed with outcome 0 at time t_0. What is the appropriate form for the ket...

Homework Statement For a particle in an isolated system, the Hamiltonian operator has normalised eigenstates and eigenvalues u_{n}(x) and E_{n}, respectively. The operator of another variable Q has normalised eigenstates and eigenvalues \phi_{n} and q_{n}, respectively. The lowest two Q...

Hi, Im am building a measurement device to measure the speed of a fan. Essentially I have a diode on one side of the fan, and a phototransistor pointing to it on the other side of the fan. This results in an output signal resembling a square wave. I am also trying to build an circuit...

I was talking to my professor about what constitutes as a measurement and the topic of the Stern-Gerlach experiment arised. *Please don't discuss about schrodinger's cat and that funny business, I've heard it many times and I am very bored of that discussion. Please no metaphysics BS, I want...

A particular muon lives to the ripe old age of 4.5 microseconds (three half lives). As it sits in its chair, ticking off the picoseconds, it observes the Earth streaking by at 99.99999995% light speed. What will be the elapsed time of the muon's life, as measured on the Earth clock? As I...

Here is a relatively simple problem. I'm wondering if someone can give me their opinion on it or actually know experimentally if it is true. Here is the diagram: A flow of liquid (say water) is pumped through a pipe that has a reduction in diameter. You place a pressure gauge before...

Hi, Could you describe the "before the measurement" mechanism in de broglie bohm theory? Is there a real collapse during the measurement? Can we determine the particle's position in its guiding function without disturbing it? Is there any way to calculate guiding function?

I don't possesses enough knowledge of GR to know if this proposal is feasible (or even remotely possible) I would welcome any constructive criticism of the following idea for detecting Lens Thirring effect: Apparatus consists of a dense, massive sphere or disc, rotating at high velocity...

1. The problem statement: A set of measurements of a parameter x has a normal distribution with mean of 50 and standard deviation of 1. If there are a very large number of measurements, approximately what percentage of measurements would you expect to be in the range 48 < x < 50...

Homework Statement I took a Moment vs field measurement of magnetic thin film taken on a VSM. The Bs of the material is given in emus. I want to convert this to a moment value in Tesla as it is typically given in publications. Are VSM measurements actually emu/cm3 despite being given as...

Does anybody understand how this wattmeter configuration is measuring reactive power? Thanks

I did some device that should be capacitor. when i try to measure capacitance I got some capacitance that varies like that:(1.5-2.5nF), but.. then i wanted to check resistance just for curiosity.. I got some result..it shows me 1.34MOhm. How it could be? As I understand it should be or...

Quantum physics texts describe how it is impossible to measure S(z) and S(x) spin components of a single electron at the same time where z represents the z axis,etc. What would happen if you try to trick nature by using a correlated pair of electons, emitted from an ion, moving in opposite...

I am curious how exactly fundamental measurements are made for subatomic particles. I am hoping someone who knows can point me to some references as to the following: 1) How is the position of a photon measured? 2) How is the position of a subatomic particle measured? 3) How is the momentum...

IQ is supposed to be the measurement of your "natural intelligence." IQ is supposed to be the measurement of your "natural intelligence." However, can your IQ vary on how much brain activity you're doing? For instance, during the Summer a person is lazy and not doing any studying or anything...

Homework Statement Find the Uncertainty Measurement using Precision Error and Bias Error? The Length of line is 5.625 in. Precision Error is 0.13 in. Bias Error is -0.115 in. What is the UNCERTAINTY measurement? Homework Equations None. The Attempt at a Solution Please help! I...

What is an observation or measurement? If it is not known exactly I would like to at least have some good appreciation of what the fuzzyness of the boundary is.