# Tagged Questions

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

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### Difference between Vernier constant and least count

What is the difference between the Vernier constant and least count of a Vernier caliper?
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### Why does hot water freezes faster than normal water? [duplicate]

What is the reason behind hot water gets Freezes faster than normal water when we keep both the hot and normal water together in freezer ?
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### Why do we get a diffraction pattern with a slit whose width is not comparable to the wavelength of the incident light?

In single slit experiments with sodium light whose wavelength is of order micrometer and slit width of order of hundreds of micron, we still observe the diffraction pattern. How do we explain this?
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### Has relativity of simultaneity been directly observed?

I know that thought experiment about trains when a flash of light in the middle reaches the both end simultaneously for a passenger but different times for the bystander. So were there (non-thought) ...
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### Linearly accelerated charge experiment feasibility

Wikipedia states: Though maybe it is surprising, there is no experiment that measures directly if an uniformly accelerated charge radiates in an inertial frame. Classic electromagnetic theory says ...
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### Interesting question to figure it out [on hold]

A 50-cm-long iron rod is heated from 20 °C to 100 °C. The linear coefficient of expansion for iron is $1.2 × 10^{-5} K^{-1}$. How to determine the change in length of the rod. By which formula?
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### Where I can find quantum entanglement, real experimental raw data

For analysis purpose, I am looking for raw data from real entanglement experiment with spin measured at two detectors, at various combinations of angles, but preferably at a single combination of ...
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### Explanation of a match between shadows and wet floor at Niagara Falls

The question is about the cause of a wet-floor phenomenon. My vacation trip started at Niagara Falls (Canadian side, horseshoe fall on the upper left corner). It was around 10-11 AM, not too sunny yet....
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### In what way has GPS had an impact on our understanding of physics?

I've been reading about the effects GPS has had on our society with the February launch of a IIF Satellite and I was wondering if launching GPS satellites and the actual GPS satellites have lead to ...
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### Why can't rotating magnets in space or zero gravity be used to create infinite energy? [on hold]

I would like to know if a system like the one below will possibly work. I understand that the laws of physics forbid the "creation" of energy but despite my efforts I haven't been able to figure out ...
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### Could Google scan books without opening them? [closed]

A few years ago, I read an article about a proposal Google put forward, as part of its paper-to-digital media project, which had the advantage of greatly speeding up the process of scanning text. The ...
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### How to find the least count of a normal scale [closed]

Well suppose i have a normal measuring scale how do i find its least count?I have just been introduced to errors in measurement and our professor was giving us least counts of different instruments ...
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### Comparison between current and voltage sensitivity

Current sensitivity of a galvanometer is defined as deflection per unit current, $$\frac{\phi}{I}=\frac{NAB}{k}$$ Here, $\phi$ is the angular deflection, k is the torsional constant of the spring, ...
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### Reference frequency

In my experiment, I have to obtain a relation between magnetic field of a solenoid and the applied Vp-p. The setup is as follows. http://www.teachspin.com/instruments/faraday/ Does my choice of ...
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### Constancy of the speed of light in the hypotenuse of the triangle in the Michelson and Morley experiment [closed]

In Michelson and Morley experiment, Michelson calculated that the total time traveled by light with respect to the stationary observer standing at ether field was $2L/c$. Here, Michelson followed ...
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### Is fluorescence from a single atom/ion visible with the naked eye (e.g. in a strongly coupled trap or cavity)

I remember sitting in on a conference talk by a person (possibly Rainer Blatt) doing research with trapped ions (or single atoms strongly coupled to light in an optical cavity), and the person showed ...
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### How correlated are the statistical significances of the same signal/non-signal for CMS and ATLAS?

Consider a diphoton excess for both ATLAS and CMS at the same energy for two cases: false signal: I'd expect the two statistical significances to be uncorrelated true signal: I'd expect the two ...
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### Self Heating in Platinum Resistance Thermometers

In order to use a PRT a small excitation current has to be passed through it, which creates a heating effect that in turn adds an error to the measured temperature. The question is this: If we have ...
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### 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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### Matter's wave-particle duality - true? [duplicate]

I had an interesting conversation with CuriousOne the other day about the question Experiment that demonstrates the wave-particle duality of electrons. I thought that wave-particle duality existed, ...
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### Has anyone experimentally shown the quantized thermal hall conductivity in Quantum Hall systems?

For background: In a $D=2+1$ state with edge modes described by a chiral $( c_L \neq c_R )$ CFT there is a predicted thermal Hall conductance associated with the gravitational anomaly at the edge. ...
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### What kinds of behavioural anomalies can a zero-field-cooled (ZFC) / field-cooled (FC) split indicate?

If a material shows a spiltting in the ZFC and FC curves, is it necessarily superparamagnetic, or could there be any other reason for the irreversibility? I have heard spin glasses also show ZFC-FC ...
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### Why is the vibration in my wire acting so oddly?

I was soldering a very thin wire today, and when I had one end firmly soldered, I accidentally bumped the wire diagonally with my tweezers. What I'd expect to happen is that the wire oscillates for a ...
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### Standard convention for $x$ error bars

What is the standard convention regarding the error bars of the independent quantity in a graph? In what situations should I show the $x$ error bars? In case both $x$ and $y$ uncertainties are ...
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### Can photons move in parallel?

Is it possible that two photons move in parallel, on the same trajectory - having the same wavelength, but differ in phase? Is it fundamentally possible on the level of quantum mechanics? Is it ...
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### Experimentally finding units of physical quantity?

Say you had a new physical quantity you wanted to determine the units for. How do you go about this? For the strength of an electromagnet for example, you could carry out a simple experiment like the ...
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### How does mass affect slipping of a rolling object?

I experimented by rolling a cylinder down a tube and noticed that by increasing its mass, it's time taken to reach the bottom decreased. Found out that mass doesn't actually affect the time taken, ...
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### Why can't weak core-less electromagnets be used in conjunction with strong permanent magnets to perpetually harvest energy?

Why can't weak core-less electromagnets be used in conjunction with strong permanent magnets to perpetually harvest energy? Magnets will attract ferrous materials but some materials like copper or ...
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### relationship between creep and hysteresis

For a particular material that's suspected to be viscoelastic, I observe a hysteresis curve where the difference in elongation between the loading and unloading curves ranges between 5% and 10% for a ...
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### necessary and sufficient conditions for linear elasticity

If it's experimentally observed that a particular elastic isotropic material has a linear relationship between stress and strain for a certain range of stresses and strains, does it follow that a ...
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### How noticeable is the gravitational pull of a mountain range?

A massive object like a planet exerts a great gravitational pull on nearby objects. This will cause them to accelerate towards the center of the planet with the same acceleration regardless of their ...
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### Milky quartz stones give off odour after being struck - persistent tribo-odorosity(?)

I have these white stones that give off a strong sulphur-like smell when struck together to produce a spark (triboluminescence). This is mostly due to hydrogen sulphide as suggested by many sources ...
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### Fiber optics with broadband, incoherent light

I wonder if someone could help clarify waveguiding with broadband, incoherent light please. If we take a telecomms fiber, which is single-moded above ~1.4 μm and couple a laser beam in, we assume ...
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### Electrostatics-Coulomb's Law

Coulomb's Law is an experimental result. The furmula that Coulomb found to describe electrostatic interactions is: $$F=k_e\frac{q_1 q_2}{d^2}.$$ How did or What did Coulomb do to verify this law as ...
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### Heat loss by radiation reference

In our lab practice, we measured the rate of heat loss of a copper plate in atmospheric pressure and the rate of heat loss of the same plate in high vacuum ($\sim 10^5 torr$). So all I could find for ...
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### A theoretical model for evaporation occurring when wind is blowing over the surface of water

I've recently done an experiment in which I was studying the variation of the cooling rate of hot water in a draft (wind). The air was blow directly over the surface of the water (kept in a ...
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### Magnetic flux density of a solenoidal electromagnet

I am designing an electromagnet which will be used to test magnetic sensors. So I used to formula found at hyperphysics which relates the magnetic field flux density to the number of turns, the ...
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### Detecting supersymmetry

What would scientists in particle colliders look for as evidence of supersymmetry?
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### Are oscillations of electron chirality experimentally observable?

Is there any plausible experiment by which chirality oscillations in electrons could be observed experimentally, such as through some analogy to neutrino oscillation experiments?
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### What's the problem with my Young slits experiment?

My Young's slits experiment doesn’t work. I mean I tried to see wave effect of light but I didn’t see any thing expect particles! I’ve sent you a pic of my laser and a short video of the experiment. ...
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### The method of measuring total nuclear angular momentum [closed]

we know that total nuclear angular momentum of deuteron is equal I=1.pleas Introduce way to this measurement (experimental way). thanks
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### About my last question of the problem of young experiment [duplicate]

as you can see Ive conducted the young experiment with these tiny tiny holes you can see in the pics but get no result again. why ? I asked and your answer was about the size of slit but these slits ...
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### What sort of experiment would directly test time reversal invariance?

I guess the title says it all: how could/would you experimentally test whether our universe is truly time reversal invariant, without relying on the CPT theorem? What experiments have been proposed to ...