Questions tagged [experimental-physics]
For questions about design, process, data, or analysis of experiments and observations.
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How is the fiber alignment done in pluggable optical transceiver module (e.g., QSFP-DD)?
I recently started learning silicon photonics. After reading a few books, I understand that a single-mode fiber (especially non-polarization-maintaining fiber) supports two degenerate guided modes. ...
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Experiments on the constancy of the speed of light with a moving detector
Are there experiments that verify the constancy of the speed of light independently of the speed of the detector, where the moving detector’s frame of reference is not the earth frame of reference as ...
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Power spectral density of laser intensity noise from a photodiode signal
I would like to get the power spectral density (PSD) of the laser intensity noise from a photodiode (PD) signal, which is picking off some light from a laser beam to be used in the process of Bragg ...
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How exactly does Rutherford's gold foil experiment confirm that the mass of an atom is concentrated at the Centre of the atom?
I have been taught that the mass of an atom is concentrated of an atom, this can be proved by invoking the fact that very few particles are deflected. However, unless I'm mistaken the deflection is ...
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Can we measure gravitational constant at high accuracy using a black hole?
It is extremely difficult to fetch accurate value of gravitational constant. How about we have a black hole toy and laboratory for it? I am (currently) not a university student and need help for it.
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How were the cathode rays concluded to be made of "particles"?
I have read about the Cathode Ray experiments which through varying the conditions led to the conclusion that those "rays" had negative charge and even we calculated the specific charge of ...
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How do I determine the orientation of the electric and magnetic field vectors in an electromagnetic wave?
I know that the magnetic and electric field vectors are perpendicular to each other and the direction of propagation of the wave. I believe that the direction of those field vectors can rotate around ...
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Suction Plates in Wind Tunnels
Let us think of a wind tunnel designed for race car applications. Suction plates plates are used to control the boundary layer and they can be placed upstream the car or under the car as well.
I find ...
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How the Stefan's law will change if the body isn't a black body?
The Stefan's law for black body radiation where energy varies with the forth power of the temperature but what will happen if the body isn't black body? Would it be still forth power of temperature ...
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Have there been any experiments that ruled out an interpretation of quantum mechanics?
Historically, have there been any experiments that ruled out an interpretation of quantum mechanics, or an experiment that could do so? I understand that interpretations are made to give the same ...
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Recreating Millikan's Photoelectric Experiment
I am designing a set-up to recreate Millikan’s Photoelectric Experiment, which is similar to all the standard online simulations. I hope to achieve this without using a vacuum as it is very expensive ...
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Is there any problem in having a stress-strain constitutive relation that relates time-derivative of stress with strain?
We usually use two empirical laws to model viscoelastic behaviour:
Hooke's law of elasticity that relates stress with strain
Newton's law of viscosity that relates stress with time-derivative of ...
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How to calculate spectroscopy limited maximum effciency (SLME) of solar cell?
The SLME technique considers the absorption behavior of absorber material and thickness of its layer with a Fermi Golden rule approach to calculate the max possible efficiency that can be drawn from ...
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What is the least count of vernier calliper which has one vernier scale division less than half of the main scale division?
What is the least count of vernier calliper which has one vernier scale division less than half of the main scale division?
Suppose one MSD be = 0.3mm and one VSD = 0.1mm.
In such a situation is the ...
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The ratio of the Higgs and QCD condensate contribution to valence quark masses
According to https://en.wikipedia.org/wiki/Quark#Mass, the quarks have the following masses.
I suppose these data in the table shows the valence quark masses, such that the uud valence three quark ...
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Papers of real experiments measuring momentum of individual particles?
I am trying to understand the different methods that have been used to measure the momentum of individual particles. I have been able to find a few methods (with corresponding papers describing the ...
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Logistics of Recreating the Michaelson-Morley Experiment
I want to recreate the Michaelson-Morley Experiment and am wondering how technically challenging it would be. I'm not looking for it to be super precise, just good enough to provide reasonable ...
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Stern-Gerlach experiment
In the Stern Gerlach experiment, one can determine the value of $j$ (eigenvalue of $J^2$) by counting the number of discrete lines formed on the screen.
For instance, if I count $7$ discrete lines on ...
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Extracting a material's band gap from the saturation current of a diode
I've been doing some analysis of some diodes for a project, including measuring how the saturation current ($I_s$) varies with temperature. (Extrapolated from measuring the IV-curve and using the ...
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Which experiments show that QED (and more generally the standard model) is correct?
It is often stated that QED makes predictions correct up to many decimal places.
What are the experiments that show this? And all have to provide measurements up to 12 decimal places?
To my ...
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How exactly does J. J. Thompson's cathode ray experiment show that electrons are particles?
I've have heard in many places that J. J. Thompson used a magnet and capacitor plates to look at the effects of the electric and magnetic fields on the cathode ray. This way, he was able to deduce the ...
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Partial pressure problem
Recently while reading the literature that ethyl alcohol has a higher partial pressure than water, thereby having a tendency to evaporate and be lost.'
My understanding is that the higher the partial ...
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Would the Rutherford gold-foil experiment work inside of an alcohol cloud chamber?
Basically as the question asks, if you set up an alcohol vapor cloud chamber with the gold foil inside, wouldn't you be able to "see" the alpha particle's path the entire time? It just seems ...
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Gyromagnetic precession of electron inside a homogeneous electrostatic field?
Would an electron placed inside a homogeneous electrostatic field (i.e. the static field between the parallel plates of a fully charged capacitor) in addition to being accelerated towards the ...
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In double-slit experiment with single atoms/molecules, how does the "gun" actually work?
In double-slit experiment with single atoms/molecules, how does the "gun" actually work?
How are the atoms/molecules "launched" to the slits?
user342647
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Metrology: How are the most accurate measurements made? [closed]
How is a most accurate measurement made when there is no other equipment to verify it? Consider you base your apparatus on a set of theory and assumptions, and the result does not match prediction. ...
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Has quantum tunnelling of an atom ever been empirically confirmed?
The phenomenon first drew attention in the case of alpha decay, in which alpha particles escape from certain radioactive atomic nuclei.
But has scientists ever observed quantum tunnelling of an atom? ...
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Gravity affects neutrons
A long time ago I asked whether gravity affected subatomic particles. An experimental physicist kindly explained that it's known to affect neutrons. Get a neutron source, and send a beam of neutrons ...
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How to interpret ion saturation current and floating potential time series in plasmas?
Let's say I have a Langmuir probe taking measurements of the floating potential and Ion saturation current inside of a plasma, which allows me to generate a time series of these quantities. There are ...
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What does it mean when people (physicists) say electron has a wavelength of $x$ unit of length physically?
When we discuss about the wavelength of em(electromagnetic) wave's wavelength,
It is meant we are talking about the tip to tip of the oscillation of electrical and magnetic field in physical space.
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What kind of experiment could measure the total sphericity of the electron's monopole charge $E$-field? [duplicate]
As far as I know this was never experimentally undertaken with a high precision measurement, probably by measuring the $E$ interaction field around the monopole charge of an isolated electron (i.e. ...
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Rate Upper Limit Inference With New Background
I am trying to set an upper limit on a process in an experiment. Over a given time period I observe $N_1$ events, which are all likely to be from a background. The background events are a Poisson ...
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Confusion about floating potential and Langmuir probes in plasmas
I am working to understand Langmuir probes and this concept of floating potential keeps popping up that I have some confusion on. I am reading a paper called Understanding Langmuir probe current-...
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Resources to learn about quantum optics lab experiments?
I would like to improve my knowledge of quantum theory by learning indepth about different quantum optics lab experiments.
I would like to find textbooks / resources which give an indepth knowledge ...
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How does the inner diameter of a copper pipe affect the time taken for a niodynamium magnet to drop through it?
Does anyone know the step by step equations to find out this question?
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Doubt in B92 quantum cryptography protocol
I am reading an article on B92 protocol which uses heralded SPDC photons. I don't understand a part of the paragraph. This paragraph mentions Bob's experimental setup for receiving the photons.
In ...
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Can you characterize a recommended experimental technique for measuring the thermal diffusivity of metals?
It is surprising that the $\alpha$ thermal diffusivity is still undefined in 3D geometry.
The current ad hoc scalar definition $\alpha$=K/$\rho$ S in normal conventions is not the best.
Currently the ...
user340804
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How do we know Uncertainty Principle is valid for macroscopic objects?
The statement "Uncertainty principle is valid for macroscopic objects" is (empirically) unfalsifiable: no macroscopic measurement is going to detect.
Yet, the majority of scientists insist ...
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Has there been any progress on resolving the $g-2$ experiment discrepancy from 2021 with the standard model?
In April 2021, the physics community was surprised by the $g-2$ experiment results and how it disagrees with the standard model.
Where can I find more progress that has been done on the issue?
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Uncertainty of the coefficient of friction
We all know the experiment in which one raises the angle of an inclined plane until right before the block begins to slide, in order to establish the static coefficient of friction.
The result for ...
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What is cocktail MC sample in physics analysis?
In high energy physics, when scientists make a physics analysis, sometimes they use cocktail Monte Carlo sample to study signal and background shape.
But I just know what inclusive or exclusive MC ...
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Can delayed choice experiment be observed live?
In delayed choice experiment an observer is added to observe the path of electron which results in interference pattern changing to clump pattern.
So if the experiment is conducted live and if ...
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How is time measured in particle experiments?
I was reading about the half life measurements and was curious to understand the experimental setups that allows so minute measurements to be captured. Specifically looking into half life of Higgs ...
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How do I convert the Amplitude from Power/Amplitude spectral density?
I've started working on PSD for seismic signals. In theory, PSD signal can be expressed in 2 ways. One in $(PSD=g^2/Hz)$ and other in $PSD=((meter/second^2)^2/Hz)$ and also ASD=(√PSD). Here $g$ is the ...
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Investigation with magnets
Take the following method for an experiment with magnets.
Method:
Hold the magnet about 1 m above the desk
Place a paperclip at the end.
Add another paperclip until the chain cannot hold any more
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Unexpected difference in experimental and theoretical results in verifying Stefan's Law
This is an experiment as part of my Experimental Physics Course in college; it involves the verification of Stefan's Law.
The experiment is pretty simple. We essentially treat an incandescent bulb as ...
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Experimental particle physics event shapes - why do different products have different event shapes?
Consider two interactions: $ \mu^+ \mu^- \rightarrow d \bar{d} $ and $ \mu^+ \mu^- \rightarrow gg $. The thrust of the down quarks will be different to the thrust of the gluon pair - why is this? More ...
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Is this a good use of the convolution?
I would like to replicate the real response of an instrument to some signal. Here's what I have in mind: I generate some ideal signal. I then add Gaussian noise to it to produce a realistic signal s(t)...
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Dust Estimation technique
I'm comparing different coating agents for ammonium sulfate fertilizer granules, coating agent is an additive to limit the dust emission, so I have a new coating agent that is lower cost and more ...
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Why we use areal density to measure thickness in different practicals of physics?
In many experiments like finding the gamma and beta absorption coefficients we use the thickness of aluminium foils in $gm/cm^{-2}$. Why we do that?, Shouldn't it be possible to only denote thickness ...
