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Questions tagged [experimental-physics]

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

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-2 votes
2 answers
58 views

Are there any experiments that examine Hamilton's Principle directly?

Or can it be examined? I 'd glad if you can share some ideas about "principles" in general.
0 votes
1 answer
36 views

Calculating Bandgap of material from specular reflectance vs diffuse reflectance

I am looking for some clarification on whether specular reflection data can be used to calculate the bandgap of a material. I am using a UV-vis spectrometer and measuring the reflectance from an ...
0 votes
0 answers
19 views

Evolution of the contact angle with a sandded ball

I study the contact angle between water and a ping-pong ball. I measured that the more I sand my ball, the more the angle decrease and the ball and increase its "wetting". Nethertheless, I ...
0 votes
1 answer
616 views

Percent difference when both negative

In an experiment, I was asked to find the percent difference between theoretical and experimental $y$-intercept (which I have). It is known that its formula is $$\text{Percent Difference} =\frac{|x_t-...
0 votes
0 answers
16 views

What are the proper steps for taking a reflectance / tranmission spectrum of a solid sample?

When I began taking spectra of samples, I was lucky to have a spectrometer that basically did everything for me and produced spectra of samples that I would expect from literature. I am now using an &...
0 votes
1 answer
97 views

Oscillation in the FTIR spectrum

An FTIR spectrum was measured for me (device from Alignment and MCT Detector) and since I'm not very familiar with FTIR I'm looking for some advice. The absorbance spectrum was obtained by measuring ...
2 votes
1 answer
250 views

Interpretation of a CLs exclusion plot

I have some trouble with the interpretation of this plot. The plot on the right shows the CLs values for the SM Higgs boson hypothesis as a function of the Higgs boson mass in the range 110–145 GeV. I ...
0 votes
0 answers
19 views

Meaning of "Typical Data Set" in Physics Publications? [closed]

I have seen uses of the term "typical data set" in reference to a graph of data of experimental results in physics publications. Is this just to point out that it is only a singular data set ...
9 votes
2 answers
2k views

Continued calibration of atomic clocks

First off I am not well versed in physics, but as I understand things the second is defined by the ceasium fountain clock which is calibrated as follows How was the first atomic clock calibrated?. Now ...
2 votes
1 answer
50 views

Will a Modified Maxwellian Demon Experiment Using Charged Particles Be Able to Recycle Heat?

(If necessary this experiment can be conducted in an environment where gravity is negligible to avoid gravitational effects.) Two adjacent containers are filled with a homogenous gas composed of ...
0 votes
1 answer
24 views

When building a fiber optic interferometer what methods are used to reduce microphonic effects?

When building a fiber optic interferometer what methods are used to reduce microphonic effects? I'm familiar with a few methods such as: enclosing the interferometer under a sound dampening cover, ...
1 vote
3 answers
578 views

Does it make sense to think about shot noise in single-photon detectors?

I am looking into the noise considerations of a single photon detector, specifically an avalanche detector. I am wondering if it makes sense to think about shot noise when considering a single photon. ...
0 votes
0 answers
31 views

Why are laser beams not affected by gravitational waves in Michelson interferometer? [duplicate]

Michelson interferometers are used to detect gravitational waves. This means two laser beams are sent in long arms and reflected at the end. Usually, they annihilate each other and no signal is ...
1 vote
0 answers
30 views

Are there any commercially made optical fibers which are made specifically to have very low microphonic properties for application in interferometry

Are there any commercially made optical fibers which are made specifically to have very low microphonic properties for applications in interferometry. While building a fiber optic interferometer I ...
2 votes
0 answers
43 views

Can we tune chemical potential by gating in solids? [closed]

Often I heard that chemical potential in solids can be controlled by gating the sample, besides other things such as doping or changing the chemical composition. How feasible is it and if any ...
2 votes
3 answers
868 views

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?
1 vote
1 answer
66 views

Why laser output power fluctuates after passing through two 1x2 fiber optic couplers?

When laser source is launched into two 1x2 50/50 fiber optic couplers connected as below the output power constantly fluctuates in range of 70 uW. The fluctuation happen roughly one to two times per ...
0 votes
0 answers
34 views

Is it possible to find a function that approximately describes data points in series?

With a pH sensor we measured the output voltage in dependence of temperature. By measuring over a temperature range we obtained a data series. That way we created several series by using different ...
1 vote
1 answer
25 views

Understanding Pressure Transmission and Lift Mechanics in a Hydraulic Lift

I'm trying to grasp the principles behind the operation of a hydraulic lift, particularly how pressure changes are transmitted and how they result in lifting actions. I have two specific doubts: ...
1 vote
2 answers
46 views

Human error in wave experiment

I am trying to see what the fundamental frequency of a string is by slowly increasing the frequency on a function generator. This experiment relies on the experimenter to record the frequency as soon ...
2 votes
1 answer
158 views

Fermilab's $g\!-\!2$ experiment: physics beyond the Standard Model?

On April 7 of this year the results of the Fermilab's $g\!-\!2$ experiment were published, increasing the discrepancy with what the Standard Model predicts. The combined results from Fermilab and ...
0 votes
1 answer
1k views

Evaporation rate of water with forced convection

A steel pot (diameter 200 mm) is fully filled with water (2 kg of water) and the water is maintained at a constant temperature of 40°C by supplying heat from an electrical tabletop burner. Assume ...
0 votes
0 answers
20 views

Electron microscopy and Interatomic distances of miller planes [duplicate]

I am studying Transmission Electron Microscopy (TEM), and have been seeing in articles TEM images of different materials typically come accompanied by these diffraction patterns, caused by the ...
0 votes
1 answer
253 views

What is the difference between a kite and a glider?

A kite and a glider, both fly without an engine. If both are unpowered, then what is the difference between a kite and a glider? Are all gliders kites? Or are all kites gliders? How do they differ? ...
0 votes
2 answers
411 views

How to Derive Generation Equation for Speed of Falling Object?

At school we are doing an experiment with a setup involving a vertically positioned ruler, a marble and a light gate. The method requires us to drop the marble from various heights on a ruler (in 4cm ...
2 votes
1 answer
228 views

Drop height vs Bounce efficiency

Hi i am analysing the graph between the Bounce efficiency vs Drop height. When i calculate the uncertainty in the gradient it comes out to be a very large number. This could be due to the small change ...
0 votes
1 answer
29 views

Fitting function to compton continuum of data measured by scintillator detector

I have measured the spectrum of $ \:^{60}$Co with an NaI-scintillator detector. Now I want to fit a function to the measured compton continuum. My idea was, that the measured counts are proportional ...
0 votes
1 answer
796 views

Insertion of current carrying metal sheet between the plates of parallel plate capacitor

A parallel plate capacitor with area of plates A and distance between them d is charged with Voltage V1. A metal sheet carrying current is inserted between the sheets. How does the system change? What'...
5 votes
2 answers
301 views

Why does detector inefficiency (or dark counts) count as a "loop-hole" in Bell-inequality tests?

Conceptually, I don't see why there is a problem with nonunity dection inefficiency or dark counts in a bell-inequality-measuring experiment. Intuitively, isn't the point of the Bell-inequality to ...
-1 votes
1 answer
280 views

Why did the air not heat up in this experiment demonstrating the atmospheric greenhouse effect?

In the paper "Experimental Verification of the Greenhouse Effect", the authors (Hermann Harde, Michael Schnell (2022)) describe an experimental setup that they say demonstrates the ...
2 votes
1 answer
756 views

Derive Charles's Law from ideal gas equation

For a thermodynamics experiment I had to determine the ratio of the volumes of two tanks. The process used was isothermal. I pressurized up one tank and slowly opened the valve between the two tanks ...
0 votes
0 answers
44 views

Where to find the Expectation Values of Aspect's and Clauser Experiments [duplicate]

Alain Aspect and John Clauser won the Nobel Prize in Physics for their epxeriments on quantum entanglement. Does anyone know where to find the raw data or at least published calculated expectation ...
2 votes
3 answers
2k views

Why is the RMS value taken to calculate uncertainty in random errors

My Text Book mentions the use of RMS (Root Mean Square) to calculate the value of uncertainty. "Random errors are handled using statistical analysis. Assume that a large number ($N$) of ...
-1 votes
2 answers
97 views

Quantum experiments at different heights from Earth

If one were to perform the same Quantum mechanical experiment say the double slit experiment or any other quantum mechanical experiments with identical conditions, set ups and elements. while ...
3 votes
2 answers
833 views

Experimental Assignment of Electronic Transitions in Atoms (Grotrian Diagram)

Grotrian diagrams often taught in instrumental methods of chemical analysis to chemists. After a decade, I finally found the original book of 1927 by Grotrian "Graphische Darstellung der Spektren von ...
0 votes
1 answer
215 views

How to calculate the direction of the missing transverse energy (MET)?

How exactly do you calculate the direction of the missing transverse energy? This paper, for example, makes use of it to get some cuts. Adding to this, how can you correlate this to the 4-momentum of ...
0 votes
1 answer
510 views

Finding out the magnetic field at anypoint outside a permanent magnet (Cylinder,Cube)

I am working in a project where I am using different shaped permanent magnets for levitation of diamagnets. I am facing problem while calculating the magnetic field around these permanent magnets. To ...
0 votes
0 answers
35 views

Second Harmonic Generation on chiral surfaces

I try to recreate a fit in this paper on SHG on chiral surfaces. I guess the question itself is too specific to get an answer, so I state these questions that are a bit more to the point (and leave my ...
0 votes
1 answer
36 views

Avoiding secondary flow in rotating fluid

I am required to create an annular flume for an experiment. The flume is to be filled with water, and a paddle is to be dipped into the water and rotated along the flume at some fixed angular velocity ...
2 votes
2 answers
341 views

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 ...
0 votes
0 answers
77 views

How did J. J. Thomson conclude that the particles present in cathode rays were not ions but are in fact much smaller than the smallest of all atoms?

What evidence did he have to prove that the particles in cathode rays are much smaller than atoms? Did he have the e/m ratio of hydrogen ion in 1897? If yes, where did he get that from?
0 votes
1 answer
25 views

Arbitrary first and second moment for squeezed spin coherent state

Consider a spin coherent state of $N$ spin-$1/2$ atoms polarized in the $+x$-direction, denoted $\lvert \frac{\pi}{2},0 \rangle$. Now, squeeze this state in the $+z$-direction with a one-axis twisting ...
1 vote
1 answer
325 views

How to measure temperature with a barometer?

I know how to use a thermometer to determine the pressure (the Clapeyron-Clausius equation) or to conduct an experiment with heating water to a boil, and look at the table of the dependence of the ...
3 votes
2 answers
85 views

Which experiments can offer insights about Hubbard $U$ parameter?

When considering $\mathrm{DFT}+U$ calculations, people either go with (1) first-principles approach: calculating the $U$ parameter using linear response theory, $\mathrm{DFPT}$, $\mathrm{ACBN0}$, etc.,...
5 votes
1 answer
3k views

Do a floor tile or dry sand conduct electricity?

If you touch an electric wire while standing on a ground made of soil or floor tile, you will get electrocuted. So, electricity passes through it. Right? Shall I conduct an experiment by passing ...
3 votes
1 answer
285 views

How to be sure that when a muon passes a detector it is actually a muon?

The question is as follows: when you have any kind of detector for muons you just take measurements and you say, for example, the number for the muon flux but how you're sure that all particles ...
2 votes
1 answer
59 views

Differential Cross Section and Factor of $\pi$

I hope this is not a double-post, but the other threads couldn't help me: In my calculations of the differential cross section $\frac{d\sigma}{d\Omega}$, I am always a factor $\pi$ lower than the ...
1 vote
3 answers
420 views

How to determine the concentration and sign of the charge carriers in copper?

I need to design a procedure for an experiment to determine the concentration and sign of the charge carriers in copper. I'm given: A slab of copper 2.0 mm thick, 1.5 cm wide, and 4 cm long One very ...
0 votes
3 answers
555 views

Establishing impact force from deceleration data

I am trying to establish an impact force. The impact came from a spear (wooden with a stone tip) hitting a soft (meat) target. The acceleration was measured by a GCDC X400-2 accelerometer. Due to the ...
1 vote
4 answers
3k views

On the relationship between slit width and light diffraction

In a light diffraction experiment, using a laser and a diffraction grid we can observe that the slits produce a diffraction pattern when the light from the laser goes through it. I have the hypothesis ...

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