Questions tagged [experimental-physics]
For questions about design, process, data, or analysis of experiments and observations.
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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,...
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Accaelaration when capacitors connected [closed]
When induced emf is produced in a circuit with resistors ( velocity not constant) accaelaration is a function of time.
But when capacitors are connected in the circuit induced emf is produced in it ...
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Question about entanglement [closed]
(There are a lot of questions about entanglement shown in the Similar Questions box. If there's already something about what I'm about to ask, please refer me there.)
Suppose the particle paths are ...
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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 ...
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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 ...
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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 ...
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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?
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Strange Homopolar motor [closed]
Do you think the motor from this video is Real.
The motor from 1:00
It Looks very strange.
Thank you.
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How do we know what physics or science textbook said is correct? [closed]
I have a question. I have a problem when learn science I like to think how they know it is this way.
When we learn physics or science from textbook we read and understand it and we have exam but how ...
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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 ...
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How is parity 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 ...
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How does the number of coils of the solenoid affect the terminal velocity of the magnet if it were to fall through the solenoid? [closed]
I was just wondering as part of a Physics project for my school if there is a formula that can govern this. I know of the equations that would describe the classic magnet falling through aluminium/...
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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' ...
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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 ...
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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?
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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 ...
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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 ...
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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 ...
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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, ...
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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 ...
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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?
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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,...
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Can the Antoine equation be used without making vacuum?
The Antoine equation is a semiempirical formula, derived from the Clausisus-Clapeyron relation, which allows the vapor pressure $P$ of a pure substance to be approximated by
$$ \log_{10}(P) = A - \...
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Gamma Ray Emission in the Wu Experiment
In the classic Wu experiment (https://doi.org/10.1103/PhysRev.105.1413) parity violation was discovered in the weak interaction through the asymmetry in the distribution of electrons in the beta decay ...
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The Validity of the Data Set of the Elitzur-Vaidman Quantum Bomb Tester Experiment
In the shown data set of the experimental realization of the Elitzur-Vaidman quantum bomb tester, at least the one published in Physical Review Letters and written by Kwiat et al., there is a set of ...
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Meaning of fanning in shear interferometers
I recently used a shear interferometer for aligning two lenses in an optical setup (a Galilean beam expander to be precise). I was able to align the lenses such that the vertical stripes were ...
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Plasma composition [closed]
Good day all,
I am looking for a way to estimate the composition of a thermal plasma formed by flowing gas between two charged electrodes.
I understand that when plasma is formed this way, it would be ...
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What evidence do we have for GR in the nonlinear regime?
The classical equations for Einstein's GR (modulo the cosmological constant) read
$$R_{\mu\nu} - \frac{1}{2} R g_{\mu\nu} = \kappa T_{\mu\nu}.$$ These equations have a complicated linearization that ...
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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 ...
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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?
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Suspiciously wrong value by factor of $1/2$ in experiment to calculate frequency of AC mains using sonometer
In school we performed the following experiment:
We use a step down transformer ($220V$ to $6V$) and pass current through a "sonometer wire". We have a meter scale underneath the wire. ...
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Accounting for air resistance in a free fall experiment
Suppose we are working with masses of equal density. The effect of air resistance is bigger on objects which have a larger surface area $A$ (perpendicular to $g$). In a free fall experiment, this ...
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Foucault's measurements of the speed of light
I understand that you can — in principle — measure the speed of light with the rotating mirror experiment.
What I don't understand: How can you accurately measure (or fix) the number of rotations of ...
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Half wave plate + polarizer vs rotatable polarizer + fixed polarizer
I am learning about optical setups and am looking at how the intensity of the laser beam is attenuated for use. A lab in my institute uses a rotatable Half Wave plate and a polarizer fixed at the ...
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What is the actual version (using electrons) of this quantum thought-experiment from an MIT lecture?
In the first lecture of the MIT quantum-mechanics 2013 course, the professor develops basic abstract concepts, by inventing hypothetical binary measurable properties of electrons (hardness (H)= hard ...
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What's the theoretical max output of the National Ignition Facility (NIF)?
With the latest Ignition event at the National Ignition Facility (NIF) producing 3.5Mj of energy, I'm curious to know. Using the pellets that they are, what's the maximum energy they could produce, ...
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How to measure the tension in a guitar string without directly measuring the frequency of the sound?
I'm looking for an accurate method to measure the tension in a guitar string, without using a sonometer setup nor by measuring the frequency.
the current method that I have in mind is to measure the ...
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Specific experiments that affirm particle-in-a-box QM theory
The infinite square well (and variations) are some of the best-studied systems in quantum mechanics and are often used as the starting point for any quantum mechanical education, as the Schrodinger ...
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Has Quantum Spin of a Single Particle Been Measured Twice Experimentally?
In quantum mechanics, the concept of spin is fascinating.
My question revolves around the experimental aspect of this phenomenon. Specifically, I'm curious to know if we have ever measured the quantum ...
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What are the two basic experiments to identify different phases in high $T_c$ cuprates systems?
what are the two basic experiments to identify different phases like antiferromagnetic, pseudogap, superconducting, strange metal and fermi-liquid in high $T_c$ cuprates systems like BSCCO and YBCO?
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SLM pulse shaping to delay (and advance) ultrashort pulses in time
I am trying to replicate some of the experiments discussed in this excellent publication:
SLM for pulse shaping
In particular, I replicated the setup configuration in Figure 14 and I want to use the ...
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How we know that Dirac equation in curved spacetime is the correct one?
Dirac equation in curved spacetime is given by
$$\left(i \gamma^\mu D_\mu-m\right) \Psi=0$$
How does we know that this is the correct equations to describe spinors in curved space time?
Is there any ...
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Is there an intuitional way to tell which physical quantities are angular frequency and which are frequency?
Such as the natural linewidth is defined to be angular frequency, while the absolute frequency of laser is frequency.
By far I haven't found a good way not to learn it by roting.
Would anyone be ...
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Probability distributions of bounded measurement results?
Say that I am measuring a length very inaccurately. For instance, I might measure $1m$ with an uncertainty of $50cm$. If I model the probability distribution as a Gaussian with $\sigma=50cm$, I run ...
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Up-to-date values of Yukawa couplings (2023)
Where can I find the most recent values for the Yukawa couplings in 2023? I currently have access to the values from 2011, but I guess precision has improved over the last decade in measurements.
Edit:...
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Cloud Chamber Help Needed! [closed]
I was inspired by this video to attempt to create a cloud chamber without dry ice (it's very challenging to get where I live) and I have had limited success so far. This is what the design looks like:
...
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Why aren't the Standard Model predictions of $R(D)$ and $R(D^\ast)$ equal to 1?
The observables $R_K$ and $R_{K^\ast}$ are defined as
$$R_{K,K^*}(q_a^2, q_b^2) = \frac{\int_{q_a^2}^{q_b^2} \frac{d \Gamma (B^{(+,0)} \rightarrow K^{(+, \ast 0)} \mu^+ \mu^- )}{dq^2} dq^2}{\int_{q_a^...
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Experimental errors and significant figures
Textbooks indicate that when reporting experimental results, the number of decimal places in the best estimate of the value (mean) should be the same as that in the standard error, e.g. 9.81 $\pm$ 0....
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How is it possible to collide particles with specific momentum in microscopic scale?
Quantum theory says particles with almost specific momentum are spatially spreaded. (have relatively large spatial scales). Then how is possible to collide them very effectively in microscopic scale? (...
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Why has it been so hard to come up with testable predictions for string theory? [closed]
String theory has yet to come up with any easily testable predictions despite decades of work.
Why is this? Why is it so difficult to come up with testable predictions for string theory?
Why is it ...
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