Measurement Definition and 1000 Threads

**Quick angular measurement question about moon. Thanks! I am suppose to write a calculation on finding angular measurement of the moon. Does the following make sense, and is correct?

Lets say we have a system in a 1D infinite potential well, prepared somehow with the wavefunction: (phi)=C(a-x)x. I understand that if I try to measure the system's energy, I will collapse the system to an eigen state ((psi)=Asin(n pi x/length)+Bcos(n pi x/length)), returning an eigen energy...

[b]1.I need to create an electronic system that automatically can measure and derive the IV and I-P characteristics (graph) and it must show maximum power point on the graphs. [b]2.The system must include a homemade voltage controlled electronic load that can load the solar cell with a well...

Maybe I'm biased because of the kind of projects I'm pursuing (raytracing), but I can't help feeling that for many areas, instead of defining a circle in terms of radians (or degrees for that matter), we should simply use unity and define say, a quarter of a circle as being 0.25. Obviously a...

In the two slit experiment there is an interference pattern generated whenever there are no detectors at the slits. This must mean that the wavefunction associated with the particles have not decohered. But the wavefunction must have interacted in some way with the barrier in order to produce...

I have an idea how to measure the ecliptic longitude with a sundial type device. Ecliptic longitude is a astronomical variable so I chose this forum. Suppose we have a verticle flag pole poised on the equator of the Earth. A "coordinate circle" is drawn that surrounds the flag pole, radius =...

Hi, i have a question about the radioactive behaviour of radium 226 and its dangers. The reason for my question is that I'm going to work in a town, where unfortunately the beach is polluted with radium 226. I'm concernced about this issue and want to know how dangerous this has to be...

Is it correct to say that a measurement occurs whenever a wavefunction interacts with a macroscopic object? If this is the case why does the wavefunction make a distinction between a photon detector and say a half silvered mirror used in quantum experiments. Both are macroscopic objects but in...

Hi, I have been assigned to a new task in my job where I have to investigate on measuring the distance to an object by means of optical interferometry (Michelson interferometry). I have been looking for info on the subject but have not been really lucky. I have been able to obtain the...

Hi tehre, this is my firs post here! I'm designing a complex system using a 40kHz ultrasonic transducers in distance measurement for waste container level detection. Now I have a big problem because the hot season change the air properties in temperature and humidity. Anyone may help me...

Where is the starting point of measurement of the Ecliptic Longitude, the Ecliptic Latitude, Right Ascension, and Declination?

Let's say we have photon beam with certain frequency. Now we make a choice to perform one of two noncomuting measurements, say polarization measurement in H/V basis or polarization measurement in +45°/-45° basis. After that measurement we perform frequency measurement. From QM perspective it is...

Hi, I have to make a coil.I do not know anything about its dimensions but know that it is to be used to measure magnetic field,its actually to be used in a magnetic susceptibility measurement.There are 3 coils, drive, excitation, measurement and I/p is given at 1000hz frequency. I need to...

I appologize if my questions make no sense (very likely as I do not have a physics background). 1. The uncertainty principle states that precision of measurement is identified only down to the Planck's constant. If this is so, how can one measure the speed of light with infinite precision? ANd...

I have to measure the particle velocity of sound waves in water. Which instrument to use to measure particle velocity of a sound in a specific direction. I searched but I find some anemometer setups for velocity measurements. I think they are all water flow measurement methods. Is there any...

is this a correct way to describe the MP? It means that everything is everywhere doing everything in every possible state at all times, until something conscious looks at it, then, as a result of the observer, it takes a state, which is only subject to how the observer perceives it. We only...

I have a code in Matlab where I need to measure the radiation on a specific latitude over a year. I have my time steps in hours and I am iterating over a year. I have parameters for the amount of radiation per hour in a 24 hour period, but my problem is that I want to loop this 24 iteration loop...

So, rookie question, I know, but I'm having a little trouble with the idea of wavefunction collapse as it pertains to stationary states: If a measurement of energy collapses a wavefunction into an energy eigenstate, it stays there forever (unless perturbed). But my impression is that although...

Can someone show me how to add, subtract, multiply and divide uncertainties in measurement.

The problem involves measurement in a quantum system with angular momentum. There are two parts I am struggling with. Apologies for the images, I tried to put it all in latex but failed! Part 1: http://i2.sqi.sh/s_1/1xo/part1.jpg I have found a long derivation in a book involving a...

Hi, I am currently trying to reconstruct three dimensional attitude only by using magnetometer measurements with the knowledge of initial attitude. There have been many research conducted on the attitude reconstruction only by magnetometer (or one vector) measurements. For example, this is a...

Hello all, I've been trying to measure the resistance of a pin, which the supplier spec at around 15mohms. I am using the hp 34401 multimeter with the 4 wire method to do the measurement. Its seems to me that when I probe the tip and the base of the pin, the resistance value is not...

Experimental "measurement" of Einstein's Field Equations The question is essentially: What if we took a strictly experimentalist view, and considered a phenomenological model for gravity that is a "generalization" of EFE: R_{\mu \nu} - C_1\ g_{\mu \nu}\,R + C_2\ g_{\mu \nu} \Lambda = C_3\...

In double slit experiment of electron, we see an interference pattern when we don’t know through which slit electron has passed and we don’t see an interference pattern when we know through which slit electron has passed. Now, to identify the slit through which electron has passed, we use...

1. Suppose in Schrodinger cat thought experiment we place a camera inside the chamber which record the events happening inside the chamber. (We are not watching inside the chamber through the camera during the period of experiment. It is just for recording purpose). After one half life of...

I have a thrust producing engine and I would like to measure the thrust from it as accurately as possible without needing the use of scales, rollers, load cells, etc. Anyway a friend of mine suggested I suspend the engine from four wires so that the wires are vertical when the engine is...

I would like to find a device to reproduce Hertz's experiment that demonstrated the transmission and reception of EM radiation. The equipment as I recall used a Leydan jar, an inductance coil to boost the voltage, a capacitor with a gap that sparked, and separately a ring with a small (I...

Following a short discussion in another thread, I promised to start a new thread for this. I asked myself the question "how would I describe the process of measurement in a fully quantum mechanical way?" and came up with this. 1) A model for the general measuring device The aim is to have a QM...

Why does decoherence not fully solve the measurement problem? I know that must have been discussed here before a lot, maybe someone can me direct to a earlier thread or post that explains it well? I read some QM texts, but they mostly do not discuss decoherence. I know something with...

Hi all, Consider a simple harmonic oscillator in the ground state. Measuring its energy yields the ground state energy with 100% probability. Now by measuring its position (thereby changing the wavefunction) and next measuring the energy again, there is now a nonzero probability of finding...

I have a question regarding probability of quantum measurement. Consider polarized photon beam that is going through polarizer. Let's assume that beam intensity is very low so that we can consider it as separate photons going through polarizer one by one. Now if we consider any single photon...

I am a little confused about a histogram of force measurements. I was asked for my physics lab to state what the vertical axis and horizontal axis represent for a histogram of force measurements? the physics lab consists of pulling a wooden block with a force sensor to record the tension...

I am trying to figure out how to combine uncertainty (in x and y) into the standard error of the best fit line from the linear regression for that dataset. I am plotting units of concentration (x) versus del t/height (y) to get a value for the flux (which is the slope) I understand how...

If I understand correctly, a measurement affects the wave function only at the moment of measurement. In other words, if one were able to compare two wave functions, one when there were measurements, and one in which there were no measurements, the only difference would be at the meager set of...

Apparently my modern electronic home electric meter uses a 'current transformer' to measure the current in order to calculate the wattage I am using. My question: is the flux generated in the current transformer also proportional to the reactive part of the current as well as the in-phase...

Is decoherence a resolution to the issue of measurement? I have read arguments on both sides.

As the title sais... Can someone explain to me what is a non-orthogonal measurement? I searched the web by i can't find any definition

In order to stop hijacking https://www.physicsforums.com/showthread.php?t=361216", I'll restart a discussion here about the role of background assumptions and the conceptual aspects of scientific theories, in particular how the "measurement problem" fits in with quantum mechanics and its...

Homework Statement my data as below diameter of copper wire/m 0.025 (mean) Unstretched part = 0.285m mass(m)/KG extension(e)/m 0.1 0 0.2 0 0.3 0 0.4 0.001 0.5 0.001 0.6 0.001 0.7 0.003 0.8...

I'm interested in doing an experimental analysis of ribbon transducers to contrast with simulations. This data could be made available to the community to aid in transducer development. A ribbon transducer consists of a rectangular element of metal foil suspended within a magnetic gap and...

Hi..please help me in designing a temperature measurement device using 8051 microcontroller. some one please help me out...with the circuit diagram please:confused:

Hi there, I am just a bit confused about the measurement of angular momentum. If we have a state which we know for sure the outcome of the measurement of L(z), the z-component of the angular momentum L, say h. Why is it that all the other components, say L(x) would not reveal itself to have...

If I had a hypothetical gravity measuring device that had no mass, would it be able to measure the gravity of a planet, that does have mass, as it approached it? Or would it not detect any gravity because the device has no mass? I hope this makes sense...

I'm looking for a device I can use to measure analog voltage (up to 25V) and send the data to a PC via USB. Only really need one input, though it wouldn't hurt to have more. My main concern is that it needs to be pretty small and light - any ideas? The few I've seen online are either too...

Hi, Hopefully I'm posting this in the correct forum. I'm using Nuclear Associates 07-451 flux detector with a gigaohm input impedance such that the measurement read is logarithmically compressed. The x-ray tube is outputting a constant number of rads. The flux sensor is mounted to the...

Hi wonder if there is anyone out there who can help me ! Whats the easiest formula for working out the measurement of curveture in a simply supported structural horrizontal monorail beam. Any help most appreciated. - thanks

Is it possible to describe the measurement process in QM simply as a perturbation to the system (either a small one or a very large one) so that effectively the eigenstates of the Hamiltonian evolve into eigenstates of an additional measuring operator? So at t=0 the Hamiltonian H turns into...

Can anyone give an example of experimient which the momentum of particle is measured in. How to detect eigenstate of momentum if its absolute value is equal 1 in whole space (idealized measurement of momentum should concern all space).

This may seem like a silly question, so I shall offer my apologies in advance. I wish design an empirical experiment to show time. I should be able to use a stopwatch to obtain a time value, say 1 s. In order to show that the value which I have measured is not due to (my) bias, I must...

Homework Statement Consider the spinor \frac{1}{\sqrt{5}}\left(\begin{array}{cc}2\\1\end{array}\right) . What is the probability that a measurement of \frac{3S_{x}+4S_{y}}{5} yields the value -\frac{\hbar}{2}? Homework Equations...