Questions tagged [experimental-physics]
For questions about design, process, data, or analysis of experiments and observations.
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The maximum air drag force doesn't coincide with the maximum velocity
I'm trying to decode my data from an experiment conducted today. We wanted to calculate the air drag acting on a pendulum. In order do to this, we first created a model for our frictional force F:
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Applying QM to a red laser
I want to see if and how can the Heisenberg inequality be demonstrated in real life. For this I consider a laser beam aimed at a very small slit, for example two razor blade close to each other.
In ...
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Symmetry in Independent electron theory
Why does the Independent electron theory, in principle, allow the symmetry of the mean field to be lower than the symmetry of the crystal lattice?
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Incentives to experimentally confirm theories after tons of experiments with various perspectives have already been run
It appears throughout history that the glory goes towards who proposes a theory and outlines the math behind it, the first person to experimentally test it, but not all the hundreds of experiments ...
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*Observational* Consequences of Energy Nonconservation in GR
What are the experimental or rather observable consequences of the non-conservation (or conservation) of energy in GR? Imagine our instruments were $10^3$ or even $10^6$ more sensitive, better ...
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Heisenberg uncertainty in position and momentum
Please clarify this confusion I have:
My understanding of quantum mechanics is this:
"The modern interpretations of the Heisenberg uncertainties state that the uncertainties in the certain ...
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How to discriminate the background and signal events in high energy physics (HEP) when they have a similar distribution on a variable?
In high energy physics (HEP), the Punzi method is usually used to optimization cut to discriminate signals and background events in some typical distributions, like PID variable, when Signal and ...
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How to determine thermal inertia of a resistor?
In a recent experiment I've done, I heated up some gas at constant volume using a resistor inside a glass bottle. I turned on the resistor for $\Delta t$ s, but I saw that the pressure rises for $\tau ...
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Efficiency of Geiger-Muller tube
What are the factors that affect the efficiency of the Geiger-Muller tube?
*the efficiency of the tube is defined as # of pulses counted per second/total flux entering the detector.
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Properties of the gas in a Geiger-Muller tube
Why does the gas filling a Geiger-Muller tube have to be inert and at low-pressure?
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Does the scattering data, in any way, justify the simplistic picture of hadrons? [duplicate]
The structure of the neutron or the proton is extremely complicated. It is not a simple bound state of three valence quarks. However, the simplified picture allows us to explain various properties of ...
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How can I become more competent in the lab? [closed]
I'm currently taking an introduction to Newtonian mechanics class(calculus-based) and I am laughably bad in the lab. So far I have a pretty solid grasp on the concepts ,but applying those concepts to ...
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Why isn't $C_v=\left( \frac{\partial U}{\partial T}\right) _v$ equivalent to $C_v=\left( \frac{\Delta U}{\Delta T}\right) $?
This might be a naive question but I just saw
$$c_v=\frac{1}{n}\left( \frac{\partial U}{\partial T}\right)_V \approx \frac{1}{n}\left( \frac{\Delta U}{\Delta T}\right)$$
Refearing to the LHS as the ...
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Experimentally Measuring the Velocity of Water coming out of an Orifice
I plan on doing an investigation into Torricelli's Law, where I will be looking at one of the following:
How the cross-sectional area of an orifice affects the velocity of water coming out of it (...
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Has been the spin magnetic dipole moment value of the free electron to be Lorentz invariant ever experimentally verified?
As far as I know all experiments measure the rest value of the spin magnetic dipole moment of a free electron either indirectly at relativistic speeds near the speed of light measuring for example the ...
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Where Does Envelope Come From In Fourier Transform Spectrometers?
Here I a Michelson interferometer setup, with an interferogram output of a monochromatic light source (laser). As the translation stage moves, the interferogram amplitude is modulated with another ...
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Meaning of quantum orbitals with $\ell=0$
My question is simple:
Does a quantum eigenstate with orbital angular momentum $\ell=0$ meaning that the velocity of the particle is only radial when measured?
What is the experimental method to ...
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Is the spin magnetic dipole moment of the free electron not at rest the same as its rest value?
As far as I know all experiments measure the rest value of the spin magnetic dipole moment of a free electron indirectly (i.e. apparently there is yet no method or apparatus to directly measure this ...
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What is the meaning of "Dual Accuracy" on this datasheet?
I'm trying to determine the uncertainty in some of my measurements, and one of the variables I measure is temperature, using a Tenma 72-7715 thermometer. I looked up the datasheet to find the ...
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Post-fit distribution
In experimental particle physics papers, often one reads "pre-fit" and "post-fit" distribution as the caption of some kinematic distribution of data and simulation.
What is meant ...
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PMT Transit time spread (TTS) for an ultrafast laser used for surface second harmonic generation?
I'm in the process of building a setup for Single photon counting in 300 - 400 nm.
Basically I'm trying to detect SHG (Second harmonic generation) reflected off of a surface. (SHG is a non-linear ...
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When finding the refractive index of a glass block should the graph be forced through the origin or not? [closed]
Experiment: To measure the refractive index of a block of glass.
A block of glass is placed on a sheet of paper and the outline is drawn. A point of incidence is chosen and the normal at the point of ...
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Does 5G affect your physics experiment?
Our institution wants to lease a nearby roof for a 5G mast. Has anyone experienced the installation and operation of telecoms infrastructure - particularly 5G - significantly affecting physics ...
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Questions about creating diffraction grating
I have a modern physics lab project this semester where we have to perform an experiment related to modern physics as a group of 3.
We choose https://aapt.scitation.org/doi/10.1119/1.5020051, an ...
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Hamiltonian not being conserved in circular motion
I've recently done an experiment where I analyzed a mass moving in circular motion around a point with a spring attached to the mass on one end and to the point around which the mass moves on the ...
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Reflection of Gamma Rays
I have an experiment with a radioactive Cs$^{137}$ source which beta decays to Ba$^{137}$. Some of the barium are in an excited nuclear state which decay to the ground state and emit a $662$ keV $\...
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How can we derive the maximum scattering angle from the experiment of Geiger and Marsden?
Schematic diagram of apparatus used by Geiger and Marsden to observe scattering of $\alpha$ particles past 90°. "A small fraction of the $\alpha$ particles falling upon a metal foil have their ...
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Combining multiple measurements: how to calculate the uncertainty in this case? [closed]
Let's say I have an experiment where I measure some variable $D$ (in the experiment I am grading it is the diffusion constant but I want to keep the discussion general). There are two runs of ...
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Does the Breit-Wheeler process produce stable electrons and positrons?
Reading this excellent experimental research (2021) outlined described also here of the first possible realization of the Breit-Wheeler photon to fermion process $γ γ^{\prime} \rightarrow e^{+} e^{-}$,...
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Based on Mie theory, will the photodiode of a sensor detect the right size of the particle wherever it is placed?
I would like to change the position of a photodiode in particulate matter sensor. I would like to know if in that kind of sensor the calculations made by the MCU are fixed for a specified angle in ...
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Milikan oil drop experiment, were there really drops that picked up only one electron?
There are representations like this:
The oil droplets can always absorb a multiple of the electrons, ultimately the simplest ratio is relevant. But such representations have even measuring points of ...
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Are the inequalities from Bell's Theorem ever actually satisfied?
Following Griffiths's description from Introduction to Quantum Mechanics, Bell's original experiment was based on the EPR-Bohm experiment, where one considers the decay of a neutral pi meson into an ...
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Is it possible to devise a physical experiment to calculate any irrational number? [closed]
Suppose we for take example $\pi$ then one nice experiment to find an approximate value for it is the Buffon's Needle experiment. Suppose we are given any arbitary irrational number $\chi$, is it ...
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Is the rate at which a material heats up dependent on its specific heat capacity?
I've recently done an experiment on heating metal bars and analyzing how they expand while heating and contract while cooling.
The experiment consists of running steam through the inside of the metal ...
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Automation and remote controlling
I am very new in the field of experimental physics. I want to pursue research in the condensed matter physics. I have observed that most of the instruments such as lock-in amplifier, digital current ...
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Does an ideal, frictionless sprinkler have a finite RPM?
According to this fluid mechanics textbook, a sprinkler with torque generated by jets (the generator in the picture being disconnected) will have an finite equilibrium RPM.
I'm not sure if this is ...
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How do they measure quantum observables in general?
In most introductory quantum mechanics books they mention as an experimental example, which demonstrate the quantum nature of measurement, the Stern-Gerlach experiment and how they measure the spin. ...
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How do we measure angular momentum in Quantum Mechanics?
In QM, we define angular momentum as
$$\hat{\vec{L}}=\hat{\vec{r}}\times\hat{\vec{p}}$$
where $\hat{\vec{r}}$ and $\hat{\vec{p}}$ are the position and momentum operators.
My doubt is: we cannot ...
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Laws of physics invariant under proper orthochronous Lorentz Transformations - experimental fact or mathematically derived?
We know that the laws of physics are invariant under proper orthochronous Lorentz transformations.
How did we come to this knowledge? Is it an experimental fact that has not been violated, or can it ...
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Does the position of the detector/observer influence the double slit experiment? At what distance is the result an interference pattern again?
Does the position of the detector/observer influence the double slit experiment? At what distance is the result an interference pattern again?
I’m asking this because the detector/observer influences ...
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What would stationary light look like? [closed]
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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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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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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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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