Questions tagged [experimental-physics]

For questions about design, process, data, or analysis of experiments and observations.

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Does the position of the detector influence the double slit experiment? At what distance is the result an interference pattern again?

Does the position of the detector influence the double slit experiment? At what distance is the result an interference pattern again? I’m asking this because the measurement influences the result of ...
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What would stationary light look like?

I mean, have we ever witnessed what we understand and call as light at rest, and what would it look like at rest?
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How can I determine the initial conditions for the fit applied to the data obtained from the ellipsometry measurement?

For thin film solar cells, I need to know the refractive and extinction coeffiecients of these materials in order to make optical calculations of some materials on the computer. For this I had to use ...
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Understanding Minima and Maxima in the Franck-Hertz Experiment

I'm trying to come to an understanding of what the maxima and minima observed in the Franck-Hertz experiment physically represent when looking at it with the collision model. I'll explain my current ...
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Relevance of scientific theory? [duplicate]

My teacher told me to find out whether or not an object that follows a particular scientific theory like the weak interaction etc. affect another object following the same scientific theory?
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Effect of the same scientific theory? [closed]

Can a body interacting with weak interaction affect another body that also interacts with the weak force? Can a body interacting with strong force affect another body that also interacts with the ...
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Though experiment of aerodynamics [closed]

If in theory there is a flying machine which can accelerate and decelerate at frequency of mhz, will sound produce by that can be heard by humans ?
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1 answer
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Rule swing with spring experiment: how can I modify it?

Basically I want to replicate this experiment (https://youtu.be/GqPGbHq2fxU). It's a ruler oscillating with one fixed end and one end attached to a spring. In my previous experiment, I used a short ...
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1 answer
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How to calculate how many $\sigma$ away is the experimental data from the theory?

I am confused with the all these how many $\sigma$s arguments. Let's say we have a measurement and we want to compare it with a theoretical value. Let's say the measurement is: M=15.1 $\pm$ 1 and the ...
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How to actually create a quantum harmonic oscillator potential well?

Classically, to put a particle in a harmonic oscillator potential I can just hook it up to a spring. But how is $V=\frac{1}{2}m \omega^2 x^2$ actually created for a particle like, say, an electron? Of ...
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What are the effects of sunscreen blocking low frequency electromagnetic wavelengths of sound? [closed]

Sunscreens block uva and uvb rays but can they block sound waves?
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Is the average collision duration $\propto T^{1/2}/ P^2$?

Question So I was reading an old question of mine and realized the average collision duration $\langle \tau \rangle $ must be proportional to: $$ \langle \tau \rangle \propto \frac{T^{1/2}}{P^2}$$ ...
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Using venturi tube for gas sample dilution?

Say I have a proposed setup as per the following illustration (Fig 1.). A pipe carries an unknown mixture of compressible gas from left to right under a vacuum (black arrows). By introducing a ...
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What's the use of curve fitting for a function $y = f(x)$, if I can reduce it to a linear regression? [migrated]

Suppose I have data points $(x_i,y_i)$, say $N$ points. I know they are supposed to fit the curve $y = f(x)$. Are there techniques more advanced than linear regression, for such cases to fit the curve?...
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1 answer
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Can an oil drop in a Millikan's Oil Drop Experiment only have a negative charge?

Wikipedia and Britannica seem to say the drops in a Millikan oil drop experiment are always negative, but can't ionization processes can either knock off or add electrons to the drop?
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How to approximate a light source as a point source of light?

A point source of light is "single identifiable localised source of something" (from Wikipedia). However, there are no true point sources of light in nature, since no object is as small as a ...
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How to correctly measure critical current density in superconductors?

In my experiments, I measure the critical currents of superconductors, and by dividing them by the cross-section areas, I derive the critical current densities. I've also seen colleagues doing the ...
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Experimentally determine the Moment of Inertia of a complex (mathematically indescribable) object

I'm a high schooler that's trying to design a robot for a physics project. The robot is a catapult; it will calculate a trajectory and shoot at a certain speed and angle using a large motor. I'm using ...
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How to find the uncertainty in the peak of a graph?

I have an experiment in which we measure dielectric constant(e) vs the temperature and the peak is supposed to be the curie temperature. I measured e for many different values of T. I want to find the ...
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1 answer
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A Friction Problem (Experimentation)

A Square dice $( 0.8$ cm $\times$ $0.8$ cm$)$ face is noted and it is released exactly $1$ cm from a ground with Friction coefficient $(\mu = 0.25 )$ (say). What is the chance that the dice rolls? ...
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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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5 answers
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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 ...
2 votes
1 answer
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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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1 answer
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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 ...
3 votes
1 answer
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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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1 answer
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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?
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3 votes
2 answers
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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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