Questions tagged [experimental-physics]

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

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Experimental foundation of particle number conservation

How can we prove that the charge is conserved in particle experiment? Or lepton and baryon conservation. I think it is easy to say that the charge is conserved, but might be hard to measure. I guess ...
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Lab Report Writing [closed]

I am need some suggestions on how to write a good lab reports on my own. I am a first year computer engineering student and in my physics course; waves and field, I have to write a lab report every ...
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Is virtual particle a relativistic or non-relativistic effect?

A virtual particle is defined to be the internal line in a Feynman diagram which usually mediates force. I'm wondering if it's a pure relativistic effect? If the system is non-relativistic (quantum ...
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1answer
113 views

Systematic+Random Uncertainty for velocity measurement

I have a question regarding systematic and random uncertainties. I have to measure the mean value of a velocity measurement in flow field at a point. I've recorded say 1000 samples in time, which I ...
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2answers
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Davisson and Germer experiment

I was reading about the experiment that confirms the wave particle duality as we see a sudden rise in galvanometer which was explained as a phenomenon of constructive interference. Is it possible that ...
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4answers
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What does the notation $8.9875517923(14)$ mean? [duplicate]

The number $8.9875517923(14)$ appears in Coulomb's constant. I have read that it has something to do with the uncertainty of the accuracy of the number but answers have been unclear. Can somebody ...
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2answers
51 views

How mass of a nucleus can be measured?

I know that mass of an atom can be measured using mass spectrometer, but how mass of a nucleus can be measured? simply by subtracting total electron mass of that atom? or there are other professional ...
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What's the insufficience and influence of standard model [closed]

standard model is a milestone achievement of modern physics.However, it still has some insufficiences, my question is: first, what are the main insufficiences of standard model? second, is standard ...
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1answer
40 views

How to measure gauge boson?

note that it's taught that in standard model particles that mediated weak interaction force are gauge bosons: vector particles, spin 1, take one charge. I'm wondering how to prove these properties in ...
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1answer
277 views

Debye-Waller factor from X-ray diffraction data

I'm conducting a X-ray diffraction experiment for lab, but am new to solid-state physics and crystallography. I have to find the Debye-Waller factor (DWF) of Al at room temperature using X-ray powder ...
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The correction of the lattice heat capacity

Some articles extracted the magnetic and electron contribution from the heat capacity by subtracting another isostructure compound (e.g. $C_p(\rm{CeRhIn}_5)-C_p(\rm{LaRhIn}_5)$). Are there any ...
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1answer
218 views

How to calculate maximum stress that can be taken by an object simply

My goal is to calculate the amount of stress it takes for an object to fracture. I would like to conduct a three point bend test, without having to buy a machine for it. The object is a pig's fibula ...
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Has the ballistic motion of an electron in gravitational field ever been measured?

Reading this question I thought of an argument that an electron's trajectory would bend in the gravitational field despite the electron's being incapable of strong interaction; this would then ...
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1answer
28 views

In the Stern-Gerlach experiment, did right-handed spin-up particles go towards the North or South magnetic pole?

Just as it says above... I cannot find a straight answer, and I have tried...
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7answers
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What is the most precise physical measurement ever performed?

Obviously some things, such as the speed of light in a vacuum, are defined to be a precise value. The kilogram was recently defined to have a specific value by fixing Plank's constant to $6.62607015\...
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45 views

How to measure the lifetime of a particle experimentally?

I'm wondering in experiment, how can one measure the lifetime of a particle, because it is a very short time. Also, I'm wondering how experimentalists measure the mass of the particle, which is also ...
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1answer
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Is it possible some of a beta decay's energy goes into a strong recoil against the nucleus?

Reading about the 'history' of beta decays and neutrinos, I learned that some early-twentieth-century physicists and chemists thought that the 'missing energy' of beta decays didn't go into Wolfgang ...
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Measuring electron spin

How do experimental physicists measure the angular momentum for the spin of an electron? A paper about an experiment would be helpful. Alternatively, how was the electron spin value of $\hbar/2$ ...
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1answer
49 views

Why supersymmetry can only be verified in high energy level?

I'm wondering why supersymmetry can only be verified in high energy level,can we check supersymmetry in low energy physics?
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202 views

How does the “Look Else Where Effect” affect the chances of detecting a false diphoton excess at the LHC?

Back in December 2015, there was found a 750 GeV diphoton excess in both CMS and ATLAS at the same location with a significance well above $3\sigma$; a 0.13% chance of being false. However, there ...
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1answer
89 views

Silly question about black hole analogues: is it possible do construct an “at home-DIY” experiment?

First of all, to the fellow Physics Stack Exchange community: I'm a undergraduate student with knowledge on basic General Relativity (GR). I do not asking this with an aim to extract relevant ...
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31 views

Error propagation in expression with trigonometric functions

In a physics lab inclined plane experiment, I am calculating the kinetic friction $\mu$ using the formula: $$\mu = \tan\theta - (a/g)\sec\theta$$ Here $a$ is the acceleration and $\theta$ is the angle ...
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1answer
155 views

Analytic Solutions to Magnetic Fields of Circular Current Loop

I came across an interesting problem and am wondering if there is a quick answer to it from someone who's done this before before I whip out the books of integral tables. Analytic expressions from ...
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0answers
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Rutherford experiment and particles [duplicate]

The Rutherford experiment proved that the Thomson model was incorrect and the Rutherford model was the right one, this because the $\alpha$ particles were deflected by the nucleus and in the Thomson ...
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Calibration of Hall Effect Measurement using Standard Reference Material (NIST)

I would like to calibrate a low-temperature Hall effect measurement using a Fe SRM. Are there any standardized Hall measurements of SRM's available?
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2answers
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Why dilute gases do not form crystals at low temperatures?

I was wondering why a dilute gas (e.g. rubidium) forms a BEC at low temperatures rather than a crystal. My (naive) reasoning goes as follows: The dominant interaction between two atoms at low ...
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1answer
25 views

Galactic structure vs distance from earth (ie age)

In both theories of galactic formation, top-down and bottom-up, we understand that galaxies become increasingly structured as they age. By increasingly structured, I mean they are more spiral or more ...
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5answers
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How do we know which direction heat flows? From cold to hot, or from hot to cold?

I'm trying to figure out which direction the heat flows. After many google searches I've determined it flows from hot (higher energy) to cold (lower energy). My question tho is, how do we ...
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1answer
47 views

Measuring cold/cryogenic objects without touching them?

A common way to measure temperature on the scale of household objects and cooking is to use an infrared thermometer. The basic idea is to look at the thermal emission of infrared light from an object ...
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Cooling a cup of coffee with help of a spoon

During the breakfast with my colleagues, a question popped into my head: What is the fastest method to cool a cup of coffee, if your only available instrument is a spoon? A qualitative answer would ...
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2answers
45 views

Is it practically possible to make an air conditioner more energy efficient?

I have had this thought for a long time that an air conditioner is connected to an exhaust device that pumps hot air away. However theoretically it should be possible to channel that air flow into ...
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1answer
44 views

What happens if we rotate one gear and this rotates another and this to another and so on. Will the last gear rotate faster than light?

what happens if we rotate a small gear attached to a larger one and the large one rotates another small one attached to a large one and the large one rotates another small attached to a large one and ...
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21 views

How to measure isospin?

In solid state physics, spin can coupled to orbital momentum in the presence of external field like electromagnetism. Since spin and isospin are both inertial degrees of freedom, I'm wondering if ...
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1answer
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Why is a laser used to split a BEC in half?

In a youtube video, a German physicist Wolfgang Ketterle showed that two halves of the condensate creates interference pattern as though they are waves. I paused the video but still unable to ...
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1answer
704 views

How to determine the focal length of a combination of two convex lenses separated by a distance $d$ experimentally without formula?

I have done this experiment to find out the equivalent focal length of a combination of 2 convex lenses of slightly different focal length and have applied the formula for the equivalent focal length ...
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How can the possibility of tritium contamination decay be removed from XENON1T or XENONnT data?

The abstract of the new arXiv preprint Observation of Excess Electronic Recoil Events in XENON1T contains the following sentence: The excess can also be explained by β decays of tritium, which was ...
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2answers
177 views

Acoustic standing waves in a bent tube

Let us consider a tube closed on one side, bent on two thirds and then a big speaker on the other end as illustrated in the following diagram: My friend and I have been debating on two main issues: ...
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1answer
200 views

Detecting the electroweak unification in data of quark gluon plasma

Electroweak unification is discussed in the Big Bang model and variant proposals, and there is a transition at energies of 100 GeV where the EW symmetry is unbroken and a quark gluon plasma phase ...
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What determines how far an incident stream of electrons will penetrate a material?

In the Davisson Germer Experiment, we assume that the incoming beam of electrons undergoes surface diffraction when it hits the nickel. That is, we assume all the electrons hit the top most layer of ...
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1answer
182 views

Remaining Potential Experimental Particle Physics Discoveries at the TeV Scale?

With the discovery of the Higgs Boson, some have been calling it the end of experimental particle physics for our generation, due to the fact that all of the particles predicted by the standard model ...
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1answer
168 views

If any, what would be the ideal modulation frequency for a phase-sensitive light sensing experiment in a non-dark environment?

I have constructed some equipment for sensing a beam of light. The equipment is enclosed in a rudimentary darkbox to block out the majority of the ambient room lighting, but is still partially exposed....
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1answer
70 views

Distinguish between measuring devices and 'sources of unitary evolution'?

In a quantum optics lab, imagine that we are given with a collection of experimental tools to set-up an experiment on an optical table. This collection could consist of devices like photon detectors, ...
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What is significant in broad and narrow resonance peak to internal structure of the resonance?

I read about the multiquark system and It seems like many people said that a narrow peak mostly likely to be a molecule structure. The broad peak seems to be a compact structure. This is like a kind ...
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330 views

Resolution in a Fourier transform spectroscopy setup

I am a bachelor physics student and as an assignment we had to perform measurements on an FT spectroscopy setup. Context. Our setup consisted of a Michelson interferometer through which the light ...
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2answers
283 views

Has Hawking radiation and black hole evaporation been observed by astronomers?

Has Hawking radiation ever been observed or has there been any attempt of observing them? Do we have any evidence that black holes can evaporate? I wonder how would one distinguish between Hawking ...
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1answer
323 views

Definition of contrast-to-noise ratio?

I have been looking at definitions of the contrast-to-noise ratio. As indicated in numerous sources (e.g. here (page 12)), the contrast to noise ratio between two signals $A$ and $B$ is: $$ CNR=\frac{...
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2answers
23 views

Activity of a radioisotope after an hour of irradiaton

Suppose that you irradiate a beam of monoenergetic alpha particles on a target. You can determine the saturation activity using Saturation activity = $\frac{R_a x \sigma \rho N_A}{A}$ But how do you ...
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Dancing behavior of a droplet

When a small droplet is dropped on a extremely hot surface (at around $220^\circ C$), it shows a dancing behavior by moving around fast on the surface. What is the concept behind this bizarre behavior ...
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3answers
446 views

Can the question of a gravitationally accelerated charge radiation be tested experimentally?

I know that the question of radiation from a gravitationally accelerated charge has been discussed extensively at Does a charged particle accelerating in a gravitational field radiate?. Yet the ...
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Doubt in huygens principle

According to huygens principle, the light should move in every direction. But when I use a torch, it just goes in one direction. Why?

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