What is Measurement: Definition and 1000 Discussions
Measurement is the quantification of attributes of an object or event, which can be used to compare with other objects or events. The scope and application of measurement are dependent on the context and discipline. In natural sciences and engineering, measurements do not apply to nominal properties of objects or events, which is consistent with the guidelines of the International vocabulary of metrology published by the International Bureau of Weights and Measures. However, in other fields such as statistics as well as the social and behavioural sciences, measurements can have multiple levels, which would include nominal, ordinal, interval and ratio scales.Measurement is a cornerstone of trade, science, technology and quantitative research in many disciplines. Historically, many measurement systems existed for the varied fields of human existence to facilitate comparisons in these fields. Often these were achieved by local agreements between trading partners or collaborators. Since the 18th century, developments progressed towards unifying, widely accepted standards that resulted in the modern International System of Units (SI). This system reduces all physical measurements to a mathematical combination of seven base units. The science of measurement is pursued in the field of metrology.
Mathematically, I understand the following eigen equation: A|a> = a |a>, where A is an operator, |a> is the eigenstate, and a is the eigenvalue. In terms of mathematics, it is nothing more than a linear transformation.
However, physically, what does the equation mean? Is it equivalent to the...
For my undergraduate project, I have been tasked to measure group delay of dielectric mirrors. I have found only papers that point mainly to use a Michelson interferometer using white light interferometry. I have googled and found how to construct a standard Michelson interferometer. However I...
Give a measurement result by the correction and uncertainty in the calibration of the thermometer indicator! With reference thermometer are measured 135.14 ° C, with another thermometer which was calibrated with reference we got the following values: 140.15 ° C 140.14 ° C 140.13 ° C 140.12 ° C...
I would like to know, does anyone know of specific examples of quantum measurement of energy? The reason I am asking is that anything that is observed is ultimately in a position space as opposed to momentum space (for example, it might be specific position of the errow of a measurement device)...
Hi guys, I am currently undergoing some measurement with TCS230 light to frequency converter, its actually a cmos color sensor, so the measurement result was made in period measurement.
For white the output was not almost the same, but actually according to bitmap resolution, the R,G,B value...
Hi,
I'm doing an experiment that gathers one data point approximately each second. I have plotted all the datapoints on a graph. The graph has many tops and bottoms. Now due to the fact that there are so many data points and that I can visualle tell that there are several overal trends: one...
Everyone,
I am a Mechanical Engineer working on a design modification (or existing product recommendation) for an Idaho National Laboratory project.
What follows is the situation description. At the end is the question. You can skip down to the bottom of the post (which details the...
Homework Statement
What is the PHYSICS metric unit for the measurement of:
a. velocity
b. mass
c. kinetic energy
d. height
e. mass
f. acceleration of gravity
g. potential energy?
What is a source that converts a great deal of nuclear energy into energy you use..{ besides...
This problem seems straightforward and easy enough, but I still want to check my answers.
Suppose the pressure of the bulb (light bulb I'm guessing used in experiment) is 20 psi (absolute) at 20C. What would you predict the pressure to be at 0C? What would you predict would be at 100C?
I...
Homework Statement
If the slope of your gradient turns out to be 4.041 s^2.m^-1 then what value would you obtain for g? State your answer in m.s^2 and to 3 significant figures.
Homework Equations
T^2 = (4 pi^2 e1 / g) - (4 pi^2 e0 / g)
This is the one I'm supposed to use. Other ones...
How do we measure the young's modulus of powders (particle size D50 is around 50 microns)?
Quasi static methods like compression , tensile etc are not recommended for powders like materials. WHat modifications do we need if one wants to use compression method ?
Hi, my group and I are doing an experiment on forces experienced on a baseball. Our setup involves the baseball attached to a motor, which is coupled to a cantilever beam (1/2 inch thick, 7 inch long aluminum rod). The beam has a strain gauge attached to it and we are recording data with...
Hello folks,
Does anyone know any formula about g-force measurement when launching into orbit? For example, 1 G at ground, 3-5 G during launching, 0 G at orbit.
Thanks,
Tim
Hello, another graduate school advising situation.
Well, like everyone else (almost), i am interested in possibility of TOK and the like;
however, since I am more of a humian empiricist I typically become bitterly skeptical of String-theory and Branes and such. Since in my opinion those...
I read two articles recently and I am wondering if I have the correct interpretation of them.
They deal with joint weak measurement and Hardy's paradox.
Is the result of the "Direct observation of Hardy's paradox by joint weak measurement with an entangled photon pair" paper indicating...
Homework Statement
If x = (7.2\pm0.6) m, determine the value of ln x with its associated uncertainty.
(Ans is 1.97 \pm 0.08)
Homework Equations
A = k{B^m}{\rm{ }} \Rightarrow {\rm{ }}\frac{{\Delta A}}{A} = m\frac{{\Delta B}}{B}
(perhaps?)
The Attempt at a Solution
i tried to...
First of all I wanted that I am not a physicist. I have an introductory knowledge gained from college, tv, news, magazines etc. So that's why came here with this question. I thought maybe you could help me with.
So the question is simple. As technology has advanced we are able to measure...
Suppose we prepare a system in some properly normalized superposition of the spherical harmonics: A|11> + B|10> + C|1-1>. One of the fundamental results of quantum mechanics is that, if we measure L_z, we will collapse the state of the system onto an eigenstate of the eigenvalue we measure. My...
I want to measure level of water at two positions in tank. How to measure it?
|-----|_> here &
| ----|_ >here
|____|
Fig. Tank
when water level reach to certain levels(1,2) o/p voltage should be generated. I hav to connect it to 24 V DC PLC i/p.
I need simple and easy solution.
PLZ help me.
Just thought I would get a couple of opinions from you guys on something I find truly amazing. In Brian Greene's Fabric of the Cosmos he explains how the delayed quantum measurement experiment works.
A single photon has already passed through a beam splitter and made the 'choice' of whether...
hello.
I am working to understand and design a UV sanitization device.
What is a good resource to learn about irradiance and its relation to distance from a surface.
Secondly, in real life, how is irradiance measured? Given a surface area, I would need to specify bulbs of certain...
What is meant by a "partial measurement" or "partial measurement in the Bell basis?"
More specifically, I'm trying to read the Wikipedia article on quantum teleportation, but I don't know what is meant when they say Alice performs a partial measurement on her qubits.
Homework Statement
Knowing the given equations, k is equal to a measurement where J(t) implies some local coupling between the observer and observed system. If a field is considered to collapse J(t), how would the two manifest into a single expression.
Homework Equations...
Say we have an electron in a position eigenstate \delta(P-x) at point P at time t_0 . We also have a detector at another point Q. At t_0 , the probability of the detector registering the electron is zero. After a certain time T , the time evolution of the wave function generates a...
If the current, voltage and power are measured at the terminals of a device containing only resistance and inductive reactance, how many values of R and X can be determined from just 1 A.C. measurement?
(P.S. This is not homework but an elec engineer who has been stumped)
hi.
as a non-physicist reading physicsbokks i have a problem understanding how, in richard feynmans words, "time itself", is measured. feynman seems to move from clock-measurement to "time"-measurement without a justification. as tsr clairly states time-dilation i have a problem of...
Maybe this counts as computational physics, or statistics I don't know where this topic belongs.
Ok so I have this nice high quality Thermodynamic measurement data and I have to start the "data raping" for results. Let's call the series A(t), and B(t) and I have a few more.
So for different...
Hi, I am doing an experiment to investigate the propagation loss in some nanophotonics structures.
The laser light is coupled to the input of the DUT chip via a tapered lensed fiber and the output of the chip is go through a objective then a photodetector.
The chip is design for...
Can someone point me to a good comparison of the various forums of temperature measurement? (Thermocouples, Thermistors, IR, etc),
I'm interested in finding out more about :
relative cost, accuracy, size, output type, any other constraints on the technology.
Reflection is not considered to be a measurement. Reflection, like using lenses is considered to be a time-reversible process. It is not a measurement and it does not erase the coherence (interference pattern)
Here is what I don't understand
What happens to the momentum of the photon? The...
Homework Statement
I have no idea how to calculate this:
Calculate the uncertainity (limit error) when you convert minutes to hours:
Minutes____Hours__
10.0 0.16
20.0 0.33
30.0 0.5
Homework Equations
They've given me like
Time Elapsed...
Homework Statement
To measure the activity of a rock thought to be radioactive, a physicist puts the rock beside a detector and counts 225 particles in 10 minutes. To check for background, she removes the rock and then records 90 particles in 6 minutes. She converts both these answers into...
Homework Statement
Let Q^(1) be the position of some object that we wish to measure, and let Q^(2) and P^(2) be the position and momentum of the indicator variable of a measurement apparatus. Show that an interaction of the form H_int = cQ^(1)P^(2)(dirac delta(t)) will induce a correlation...
Do quantum logic gates perform measurements? (collapse the wavefunction)
For example:
If I apply a cNOT gate to a pair of cubits with wavefunction 1/\sqrt{2} |10> + 1/\sqrt{2} |00>
what would I expect as the result?
1/\sqrt{2} |11> + 1/\sqrt{2} |00>
?
or
1|11>
or
1|00>
or...
if there are two identical systems,in quantum mechanics(or any other theorem),according to schrodinger equation, they will evolve congruously.but from the instant of measuring,the evolution seems disobey its original principle----i mean the evolutions are not congruously any more.
is that mean...
Description of method: The rotor's mass is constant so when it accelerates in a given wind, it does so with an acceleration = torque/mass. This acceleration will depend essentially on wind speed. If tests are carried out in the open with non-turbulent winds it is possible by using a tachometer...
I want to measure the temperature of a metal surface surrounded by glass with a near infrared pyrometer(1.45 micron to 1.7 micron). I am not sure the influence of the glass on the measuremental accuracy. You know the infrared radiation may be absorbed by the glass to make uncertainty.
Please...
Homework Statement
The Shadow cast by a vertical pillar in Alexandria at noon during the summer solstice is found to be 1/8 the height of the pillar. The distance between Alexandria and Syene is 1/8 the Earth's radius. Is there a geometric connection between these two 1-to-8 ratios...
[b]1. I recently had a lab on free falling and have all the data and percentage amounts from the data sheet, and Position vs. Time.
I'm having a problem creating the slope for the velocity vs. Time. Do I use two different points or just one point?
I used to different tangent lines...
I know that σ is the symbol typically used for standard deviation, but what does the use of σ mean in these contexts?
ex. 1: "[our fancy new instrument] ... allows for the identification of > 500 sources at greater than 10-sigma"
ex. 2: "These estimates assume ... a 1σ polarization...
NEW TECHNIQUE FOR RESIDUAL STRESS MEASUREMENT NDT
Introduction
Internal stresses are to be considered as the following: 1) Operational strains referring to loads that the material is subject and calculated 2) Residual stresses in the material caused by heat treatments or stresses caused...
Measurement is probably the most important act when we attempt to understand our universe; without measurement we would have no information at all. The problem is including measurements in our theory leads to complications which our difficult to describe. I will outline a couple of the problems...
Hello, first of all sorry for my bad english it is not my mother tongue
I am new to the uncertainty and significant figures concept and I have measured some things, I want to write the results using them.
The length of my table is 273,3 cm. The instrumental uncertainty is ± 0,3 cm, and I...
Homework Statement
Lets say m1 = 80 +- 0.1 g and m2 = 60 +- 0.2g and p = 1.0 g/cm^3 +- 0.1 g/cm^3
I want to solve for V and V = (m1-m2)/p
What would the uncertainty on this be?
When you subtract the two masses, it becomes 20 +- 0.3g.
You divide that by 1g/cm^3 +- 0.1 g/cm^3.
0.3...
I have a question that has been bugging me lately. How is it that you determine the total error of a measurement?
For example, if we are trying to measure the flow rate of water coming out of a hose. We let the water flowing through the hose fill a graduated cylinder and measure the time it...