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Questions tagged [experimental-physics]

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

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Refractive index of titanium dioxide films as a function of wavelength for 400 C ° annealed films

I used UV-Vis/NIR spectrophotometer to extract the measurements of refractive index %R corresponding with wavelengths in the range of 190-1100 nm of TiO2 thin film deposited on FTO glass substrate. ...
Mona's user avatar
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0 answers
45 views

Getting the power spectrum from an interferogram

I'm doing analysis for a laboratory task where we used a stepper motor to vary the position of a mirror (in a Michelson interferometer) to get interferograms using different light sources. I have been ...
elina's user avatar
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1 vote
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Offset in fortuitous coincidences in Na22 PET scan

I'm doing a PET scan for a Na22 radioactive sample and analysing the fortuitous coincidences. To measure the fortuitous coincidences I put both detectors in a 90º angle and gathered the number of (...
ludicrous's user avatar
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120 views

How does an Abbe refractometer actually work?

I'm now in the process of writing a report on a lab work i did with an Abbe refractometer. In all sources i found the working principle of this refractometer is described as such: "Light shines ...
Tom4211's user avatar
-2 votes
1 answer
65 views

In what media has the electric charge of an electron been measured? [closed]

I need specific references of experiments that have measured the electric charge of an electron in different media (water, air, others). I have found some performed in air or vacuum (Millikan, Thomson,...
Juan Moreno's user avatar
1 vote
0 answers
50 views

Why is the fermionic sector of Standard Model the way it is? [closed]

"Because it works!" will be considered too broad an answer. I want to precisely know which experiments forced to consider the model construction the way it is. For example, I can see Wu's ...
Sanjana's user avatar
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30 views

Coupled degenerate wave equation and heat equation via transmission with Gurtin-Pipkin or Coleman-Gurtin thermal law

I am a mathematician and I am working on studying the stability of coupled degenerate wave equation and heat equation under with Gurtin-Pipkin or Coleman-Gurtin thermal law. The classic wave equation ...
i.issa's user avatar
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0 votes
1 answer
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$\rm NaI$ detector calibration with $\rm Cs$-137 and $\rm Co$-60 using Genie-2000 software [closed]

I have tried to calibrate the NaI detector with the NIM set, Cs-137, Co-60 radioactive sources and Genie 2000 software. I used Cs-137 first and corrected the channel energy then used the Co-60, only ...
DrrMickey's user avatar
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0 answers
37 views

Locking of 480 nm laser using EIT

I am trying to lock 480 nm laser using EIT by frequency modulation technique. For this I have modulated the probe beam using 10 MHz phase modulated EOM, and trying to observe sidebands both right and ...
Monika Thakran's user avatar
1 vote
1 answer
46 views

What is the optimal measuring time split for limited measuring time between signal+background and background in a Poisson counting experiment?

I’m trying to figure out the best split of time between measuring either background or signal+background in a counting experiment in the case where we have no prior knowledge about the mean signal ...
Physicist_285's user avatar
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0 answers
21 views

Doubts about Pasco photoelectric apparatus

I've doing an experiment with Pasco photoelectric, but when plotting the intensity-voltage curve I got that the 436nm line is over 405nm. But that's normal because the intensity of the 436nm line is ...
Guillermo Fuentes Morales's user avatar
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1 answer
78 views

Why small particles are attracted by charged objects?

Everyone knows this experiment: You mix salt and pepper and use a charged balloon to separate the pepper from the salt. I never really understood how this works. In school (long time ago) we learned ...
flappix's user avatar
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0 answers
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How to drop straight a cup of water with a ball within it? [closed]

I want to drop a cup of water with a ping pong ball within it so that it falls straight (as much as possible) and that I can reiterate the experiment rigorously... I've seen someone using magnet and a ...
Dlouna.J's user avatar
0 votes
0 answers
33 views

Modeling the difference between DC and AC current in a superconducting coil

I have an application I'm trying to model that involves using superconducting coils to produce a steerable dipole. To some degree, the problem is easier if I can modulate the current through the coil, ...
reivax's user avatar
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-1 votes
1 answer
230 views

White Holes Evidences

It is well known that in the canonical quantization program for quantum gravity, like LQG/Wheeler-De Witt/Polymer QM, almost every prescription when applied to cosmology/gravitational collapse leads ...
LolloBoldo's user avatar
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1 answer
43 views

Impact of photodiod's active area density on quantum efficiency?

The quantum efficiency is a factor, telling me the ratio between optical input and electrical output. So I wondered, how does the efficiency depend on the density of the photodiod's active area? I ...
iwab's user avatar
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2 votes
1 answer
117 views

How to explain this observation in Franck-Hertz experiment?

We did the Franck-Hertz experiment in our physics lab. The setup was like this We fixed the value of $V_{G_{1}K}$ and varied the values of $V_{G_{2}K}$ and got the curve for the electron current vs ...
Ankit's user avatar
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2 votes
1 answer
61 views

Laser beam quality problem: The laser beam showed very different during using the CCD testing directly or using the M2 measurment machine

Recently, we encountered a problem with the laser beam profile characterization, where two testing methods showed two distinct results of the beam profile of the same laser system. When we used a CCD ...
李文嘉's user avatar
2 votes
1 answer
70 views

Sensitivity of different elements to neutron activation analysis

When I look at Ortec AN34 Experiment 17, I see that the last page shows relative sensitivity to Neutron activation by weight for different elements. For example, the analysis of Fluorine is shown as ...
user192428's user avatar
3 votes
1 answer
55 views

Experimental evolution of condensates

I was talking to a colleague professor the other day and he said something that got me curious. The way I remember it, he said basically that in experiments a Bose-Einstein condensation is usually ...
JustWannaKnow's user avatar
0 votes
1 answer
54 views

What can one say about the precision of the experiment if horizontal error-bars are wide and vertical error-bars are very small?

After conducting a physics experiment I plotted the data with their respective uncertainties. My horizontal error-bars for the independent variable are wide but vertical error-bars for the dependent ...
Alex's user avatar
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2 votes
0 answers
44 views

Stern-Gerlach Experiment vertical atom distribution

From some of the videos covering the Stern-Gerlach experiment I noticed that electrons / silver atoms that are shot through the magnet are visualized to spread not only into two distinct horizontal ...
Ruslan Plastun's user avatar
1 vote
0 answers
84 views

Visualizing helium’s interacting electrons [closed]

I want to numerically simulate the experimental results seen in this Phys. Rev. Lett. paper, specifically the interference patterns of ionized helium. The authors used photoionization microscopy to ...
Medulla Oblongata's user avatar
4 votes
0 answers
77 views

Question about spin-$½$ particles

Spin-½ particles needs to rotate 720º to return to its original state. If you rotate it 360º, its state will become opposite, for example $\left| ↑ \right>$ to $-\left| ↑ \right>$. This is my ...
Max0909's user avatar
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1 vote
1 answer
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What referential should I use? Ping pong and water cup

I'm trying to modelise the ping pong and water cup experiment. They were already questions on stackexchange about this: Why does a ping pong ball bounce higher when it is dropped together with a cup ...
Dlouna.J's user avatar
0 votes
2 answers
436 views

Calculating average from several independent physical experiments

If I have 2 experiments measuring the same thing. For example, I measure the voltage with 2 different tools (2 different voltmeters). I can calculate the final average in 2 different ways. For example,...
Zlelik's user avatar
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0 answers
74 views

Reasons of laser power low frequency fluctuations

I have fiber-coupled laser source - Thorlabs S1FC635, single-mode. I research the long-term instability of laser power. My experimental setup contains Thorlabs S1FC635, single-mode fiber connected to ...
U_K's user avatar
  • 1
0 votes
2 answers
91 views

Nuclear binding energy and gravitation

A nucleus $A$ can be split into two smaller nuclei $B$ and $C$. It is well known that the sum of the masses of $B$ and $C$ will not equal the mass of $A$ due to the nuclear binding energy and the ...
Jagerber48's user avatar
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1 vote
0 answers
58 views

Did the distances of the reflecting mirrors in Michelson Morley need to be precise to 100 nm or less?

When I took Physics, both in HS and College I was taught that the reason the Michelson Morley experiment "could" produce an interference pattern at the detector location was that the two ...
Joseph Hirsch's user avatar
-1 votes
1 answer
159 views

In four probe experiment why the graph looks like in low temperature

I found a graph between the log of resistivity vs inverse of temperature like this So in region 2, why is the graph going down?
Joy's user avatar
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8 votes
10 answers
2k views

How do we know what physics or science textbook said is correct? [closed]

I have a question. I have a problem that when I learn science, I like to think 'how do they know this is right?'. When we learn physics or science from a textbook, we read and understand it, and then ...
Heroz's user avatar
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0 answers
59 views

Measurement paradox

When building electronics to measure usually it is asked what the bandwidth of the signal is and what is the frequency range usually done to limit noise bandwidth and thus have more SNR. To me it ...
Weijie Chen's user avatar
9 votes
1 answer
259 views

How is parity of the deuteron measured experimentally?

I'm reading Wong 'Introductory Nuclear Physics' and in chapter 3-1 he writes that "For the deuteron, it is known that the parity is positive. Let us see what we can learn from this piece of ...
jkcwioqnkfdsoia's user avatar
0 votes
0 answers
23 views

How would red (frequency) shift work for sound waves on the surface of a balloon?

Imagine an expanding balloon with a source of vibrations, in the fabric of the balloon, on one side (pole), and a microphone on the other side (pole). We would expect the sound to be 'red shifted' ...
John Hobson's user avatar
0 votes
1 answer
78 views

Atoms in the cavendish torsion balance

Some people who try to deny the Cavendish Experiment say that the masses attract each other because of the atoms, not gravity. Doesn't an atom have a null electric field by nature? Is there any other ...
doca's user avatar
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0 votes
1 answer
135 views

What is the difference between nanomaterials and quantum materials? [closed]

As per my knowledge, they are different according to their dimensions only. Can you please explain if I am missing something?
Sudeshna Sahoo's user avatar
0 votes
0 answers
21 views

If the conductor floats in a horizontal homogeneous magnetic field, what is the current?

If the conductor floats in a horizontal homogeneous magnetic field, its magnetic flux density is 0.75 T and one meter of conductor weighs 2.5 g. How to calculate current. So when the length or mass is ...
Violettttt's user avatar
0 votes
0 answers
16 views

How accurate is coincidence counting, and how do we know?

Experiments that feature the creation of entangled photons through SPDC often make use of coincidence counters. How can one photon be accurately correlated with its entangled partner by a coincidence ...
OneStrangeQuark's user avatar
4 votes
2 answers
563 views

Least Count Error is Random or Systematic?

There are so many articles on internet on Error analysis in measurement but some of them relate least count error with systematic and other with random error and some associate it with both of them. I ...
Govind Prajapat's user avatar
5 votes
2 answers
415 views

When was it possible to observe the special-relativistic modification of Energy?

I am preparing a lecture for high-school students, and was wondering when it would have been possible to observe the special-relativistic modification of the Energy-velocity relation. In more detail, ...
Mario Krenn's user avatar
0 votes
0 answers
85 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 ...
Double_you's user avatar
1 vote
2 answers
103 views

Air resistance in the Cavendish Experiment

Would air resistance be an issue in the Cavendish experiment or are the velocities so low as to be irrelevant? Could it cause the experiment to fail?
doca's user avatar
  • 31
0 votes
0 answers
99 views

What is the benefit of using entangled photons for ghost imaging compared to just spatial correlated photons?

I am planning to work in quantum ghost imaging. I will be using a type 2 entangled spdc source which is already there in the lab. I need to know what will be the effect of using polarization entangled,...
QuantumOscillator's user avatar
1 vote
1 answer
149 views

Gamma Ray Emission in the Wu Experiment

In the classic Wu experiment (https://doi.org/10.1103/PhysRev.105.1413) parity violation was discovered in the weak interaction through the asymmetry in the distribution of electrons in the beta decay ...
jkcwioqnkfdsoia's user avatar
4 votes
1 answer
217 views

The Validity of the Data Set of the Elitzur-Vaidman Quantum Bomb Tester Experiment

In the shown data set of the experimental realization of the Elitzur-Vaidman quantum bomb tester, at least the one published in Physical Review Letters and written by Kwiat et al., there is a set of ...
OneStrangeQuark's user avatar
0 votes
0 answers
8 views

Meaning of fanning in shear interferometers

I recently used a shear interferometer for aligning two lenses in an optical setup (a Galilean beam expander to be precise). I was able to align the lenses such that the vertical stripes were ...
AccidentalTaylorExpansion's user avatar
1 vote
0 answers
34 views

Plasma composition [closed]

Good day all, I am looking for a way to estimate the composition of a thermal plasma formed by flowing gas between two charged electrodes. I understand that when plasma is formed this way, it would be ...
Mr MoChem's user avatar
7 votes
1 answer
311 views

What evidence do we have for GR in the nonlinear regime?

The classical equations for Einstein's GR (modulo the cosmological constant) read $$R_{\mu\nu} - \frac{1}{2} R g_{\mu\nu} = \kappa T_{\mu\nu}.$$ These equations have a complicated linearization that ...
Panopticon's user avatar
1 vote
0 answers
15 views

How does MEMS low insertion loss fiber optic switch work? [closed]

I'm currently looking for a low insertion loss fiber optic switch to be able to change the light source of a spectrometer. Since this will be used in harsh conditions, I was hoping to find one with no ...
coffee's user avatar
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0 votes
1 answer
21 views

Why were multiple layers of absorbers and scintillators used in the CMS HCAL?

Why were multiple layers of absorbers and scintillators used in the CMS HCAL? Couldn't they have used just one absorber and one scintillator layer? Why was the choice made to have multiple layers?
secondquark's user avatar

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