Questions tagged [measurements]
For questions related to methods, analysis, accuracy, presentation, or interpretation of measurements. It is not intended for abstract quantum measurement questions such as how a wave function collapses during measurement or how the Heisenberg uncertainty principle constrains quantum measurements.
1,320 questions
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Is the bond angle of the water molecule known to differ (if only by a small amount) from the arccosine of $-1/4$?
Wolfram alpha says $$ \arccos(-1/4) = 104^\circ \, 28' \, 39'' $$ plus about one-fifteenth of a second. Are there physical measurements that establish (with high probability) that the bond angle of ...
2votes
1answer
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Multimeter cannot read the capacitance
I am making a DIY Paralel Plate Capacitor with the dimension of 27.5cm times 4cm seperated by 80 gsm paper. Assuming paper thickness is 0.1mm I should get around 3.6nF. But when I test using my cheap ...
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1answer
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Is mass (measured on a balance scale) the only truly universal measurement? [closed]
It is often held that c is universal, but that is only true to a local observer because the flow of time is different in different gravitational fields and at different speeds, so c itself changes to ...
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1answer
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Standard deviation on particle detector efficency
First time posting here, so indulge with me if I do not respect yet the formatting. In the context of a particle physics work, I am studying the efficency of a detector. More precisely, its efficency ...
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3answers
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Why periodic motion as a clock?
Isn't it circular to say that we use periodic processes to define a time interval? Because in order to determine whether a process is periodic, i.e. whether the same changes always repeat at the same ...
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The width of asymmetric distribution [closed]
What is the meaning of dispersion or standard deviation, calculated by definition, in case of asymmetric distribution? What is the measure of asymmetricity of such distribution?
5votes
2answers
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How exactly does a camera measure the electromagnetic field?
I know that a camera does not directly measure the immediate value of the electromagnetic field's vector, but rather the average value of a derived quantity (a statistic of the EM field). Perhaps this ...
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Why wavelength cannot be measured at one point?
It is said that the wavelength of light cannot be observed at a fixed point because it is the spatial distribution of the electromagnetic field, but I don't understand it well. Please explain it in an ...
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How to experimentally measure superposition of a quantum system?
If we have a state in a superposition, e.g. $\lvert \psi\rangle = (1/\sqrt{2})(\lvert\phi_1\rangle + \lvert \phi_2 \rangle)$, how to experimentally measure this superposition? I know that the ...
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1answer
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Can classical measurements be recovered from quantum mechanics?
The classical concept of measurement is simply defined as the determination or estimation of a quantity. On the other hand, a quantum measurement involves the `collapse' of a wavefunction (in the most ...
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2answers
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Generating static charges with known values in the order of some $\rm pC$ through DC power supply
I need to conduct some laboratory experiments that require transferring a known quantity of static charge onto a metal ball with a 12 mm diameter using a DC power supply. After transferring the charge,...
1vote
3answers
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Oldest measurement still in use [closed]
What is the oldest measurement still in use today? [See more precise version further on.] That is, the oldest result (the datum) of measuring something, that is still used nowadays as-is, that has not ...
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Detailed Exploration of Hartley Gravimeter Design
The Hartley gravimeter is an intriguing instrument used in geophysical measurements to detect variations in gravitational forces, but the reasoning behind its design remains somewhat unclear. I’ve ...
user179370
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0answers
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GPS for direct velocity measurement
Is it possible to use GPS (satellites with atomic clocks + signal transmitter, plus receiver hardware) to measure the velocity of the receiver directly instead of measuring the location of the ...
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2votes
3answers
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Addition v/s multiplication in significant figures
Say, I measured the length of a rod to be 2.5 units, now I place 4 such rods in line, what will be the length of the new rod? will it be: a)10 b)10. c)10.0 My dilemma: If I multiply $2.5\times4$, as 2....
