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

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1answer
116 views

Is there any way to find difference between two same sounds of different people?

I am trying to understand and find a way to distinguish two same sounds of different people by some physics formula, so could you guys help me? OK I'll try to explain my question in this way that, ...
2
votes
1answer
33 views

What will happen if we establish a physical connection between ground and ionosphere?

https://en.wikipedia.org/wiki/Ionosphere The ionosphere is a shell of electrons and electrically charged atoms and molecules that surrounds the Earth, stretching from a height of about 50 km (31 mi) ...
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3answers
33 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 ...
1
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1answer
29 views

Verify Faraday's law of induction [closed]

I need to design a procedure for an experiment to verify Faraday's law of induction. I'm given: A Helmholtz coil of radius 15 cm Three plastic spheres of radii 1 cm, 1.5 cm, and 2 cm. A spool of ...
0
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1answer
205 views

Error calculation for experimental data

I have the list of experimental values: $$\{w_i \pm \Delta w_i\},$$ where $w_j$ is a mean value and $\Delta w_i$ is an error. I want to calculate the second list $\{a_i \pm \Delta a_i\}$ according to ...
0
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1answer
37 views

Which experiments of harmonic generation at low frequencies preceded Franken's SHG?

In The Principles of Nonlinear Optics by Shen, he says that the generation of harmonics at low frequencies were long-known before Franken did SHG in the optical range. Franken's idea was simple. ...
0
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1answer
32 views

Basic high school physics question, on measuring voltage from CRO screen:

My textbook says 'this represents a voltage that varies from +300mV to -300mV. If this voltage were measured using a meter a value less than this would be displayed since the meter gives an average ...
1
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0answers
29 views

Effect of shielding on a miniature Helmholtz coil

So a bit of background... I'm a university graduate student with primarily digital signal processing and embedded experience. However I've managed to get myself involved with a project that requires ...
27
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5answers
4k views

Interpretation of “transition rate” in Fermi's golden rule

This is a question I asked myself a couple of years back, and which a student recently reminded me of. My off-the-cuff answer is wrong, and whilst I can make some hand-waving responses I'd like a ...
8
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3answers
967 views

How are the 4 km arms of LIGO measured so accurately?

The arms of the LIGO interferometer are 4 km long. Now, LIGO functions by measuring phase difference between two beams of light comming (as in Michaelson's Interferometer) to a sensitivity of $10^{-18}...
0
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1answer
33 views

How to interpret these gravitational lensing data?

The data I am trying to understand this gravitational lensing data in the link above. However, unfortunately I don't have an extensive knowledge in physics. Could someone please tell me what each of ...
10
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1answer
275 views

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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0answers
20 views

How is a frequency comb used to stabilize other lasers?

So I am currently in the process of writing my bachelors thesis which partly concerns frequency combs. I have read that some of the applications is: Optical measuring tool. (by detecting beat-note) ...
2
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2answers
71 views

Muon lifetime determination

My colleagues and I performed several experiments to determine the lifetime of the muon (from secondary cosmic rays) using scintillator detectors coupled to multi-channel analysers. The results ...
7
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1answer
180 views

How are LIGO mirrors cooled?

The recent LIGO announcement Observation of Gravitational Waves from a Binary Black Hole Merger has some technical details about LIGO. For example, LIGO is a modified Michelson interferometer. The ...
0
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2answers
73 views

How are laws proven in general?

This may be a bad question, but what are the ways that laws are proven? I would expect that some ways would include by proving them mathematically or through experimentation. My biggest question about ...
1
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0answers
139 views

What is the significance of the possible new 17-MeV “protophobic X boson?”

Krasznahorkay et al ...Possible Signature of a Light, Neutral Boson published results in 2015 of a possible new particle at 16.7 MeV+/-0.35. The researchers suggest "such a boson might be a good ...
46
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3answers
2k views

Why are LIGO's beam tubes so wide?

Gravitational wave detectors and particle accelerators have at least one thing in common -- they require long vacuum tubes through which a narrow beam is fired (a laser in the gravitational wave case, ...
1
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0answers
27 views

High pressure deformation of metals

Does copper undergo elastic recovery after being exposed to high pressures (above 30 GPa in a diamond anvil) at room temperature?
47
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4answers
4k views

Why does LIGO do blind data injections but not the LHC?

The LIGO group has a team that periodically produces fake data indicating a possible gravitational wave without informing the analysts. A friend of mine who works on LHC data analysis told me that ...
4
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2answers
137 views

Why do we learn only two computations, cross sections and decay rates, in such a fundamental theory as QFT?

When I learned Newtonian mechanics I found a vast variety of computations that I could do and that was so interesting. And it was so when I learned Maxwell theory. When I started learning QFT I hoped ...
2
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2answers
75 views

Experimental confirmation of the textbook explanation for local entropy reductions

Clarification: In my original wording of this question, regrettably, I did not make it clear that I am interested in the the Boltzmann/Gibbs/statistical (BGS) interpretation of it, as opposed to the ...
1
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1answer
27 views

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 ...
0
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1answer
50 views

Are pure Dirac fermions (electrons, quarks, …) allowed to have effective Majorana mass?

Charged particles such as electrons and quarks are not allowed to have a hard Majorana mass (see here). With 'hard' I mean an explicit mass term in the Lagrangian which would break the corresponding ...
1
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1answer
230 views

Thought Experiment: Force on magnets in a Stern Gerlach Experiment

Background: In the SG experiment, an inhomogenous magnetic field affects a force on particles passing between two magnets. "Measurement" takes place when a screen is placed on one end, blocking one ...
2
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2answers
56 views

Why don't reflector telescopes place their reflectors at an angle?

To avoid placing a secondary mirror in front of the objective mirror, why not tilt the objective and design the eyepiece in such a way that comatic aberration is minimized?
3
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1answer
41 views

How can I determine whether balloons inside a balloon are filled with the same gas?

We recently awarded ourselves some helium balloons to celebrate something, and they came with about a dozen little balloons inside, filling it to just under half way. I was discussing with a ...
8
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2answers
149 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 ...
9
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1answer
68 views

Measuring tides in a swimming pool

The tidal range of a perfectly fluid inertialess ocean on the Earth (taking into account lunar tides only) is approximately half a metre: this is the range between "high" and "low" points of an ...
1
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1answer
28 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 ...
1
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1answer
26 views

Young's modulus and geometry of test material

When measuring Young's modulus in a material, does the geometry of the material actually matter? I have seen several references recommend that I use cylindrical pieces. But, wouldn't the tests work ...
1
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1answer
34 views

Can vernier scale ratio be less than 1?

I came across a question (See Image) that states about two vernier scales The first vernier scale is the top-most figure in the image: It has 10 vernier scale division equal to 9 main scale division ...
8
votes
1answer
552 views

Calculation of water bulk modulus using equation of state

I simply want to calculate the bulk modulus of water at 50C and increasing pressures. I think I am correctly calculating the new specific volume from the original conditions at (25C and 1atm) to 50C ...
10
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2answers
8k views

What is $p_T$? (transverse momentum?)

I've been looking at a few papers in experimental physics (from the ATLAS collaboration, for example) and I've often run across phrases such as "high-$p_T$ electron." What exactly is $p_T$? Is it ...
0
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0answers
12 views

Transverse momentum [duplicate]

I'm having an introduction on detector systems in particle physics. The sources I read constantly talk about the measurement of "transverse momentum". However, I cannot find a definition of what is ...
2
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2answers
146 views

What will be the effect of placing a light source very close to a photodiode?

What will be the effect of placing a photodiode really close to a laser source and what should be the appropriate distance between a light source and photodiode to get maximum output current?
5
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1answer
51 views

Optical Retroreflectors: How Are the Faces So Accurately Righted?

This question is about Optical Retroreflectors (corner cubes) and how the extreme precision in their manufacturing is achieved. I suspect there is interesting basic physics involved, which is why the ...
7
votes
5answers
1k views

Final theory in Physics: a mathematical existence proof?

Some time ago, I read something like this about the issue of "a final theory" in Physics: "Concerning the physical laws, we have several positions as scientists There are no fundamental physical ...
1
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1answer
39 views

Why surface tension behaves so differently?

When a needle (or any other object) floats on water, its acting upwards balancing the gravity. But when an object (or may be a needle suspended in water) submerged in water, it acts downwards. ...
1
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2answers
55 views

Lamina Pendulum Experiment help

I've been tasked with researching ways to find the gravitational acceleration g and its uncertainty together with the moment of inertia and and the moment of inertia's uncertainty. I have figured out ...
1
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0answers
27 views

Four point probe method under liquid nitrogen

I was trying to measure the resistivity of the YBCO superconductor (but not like a resistivity- T diagram, but only at liquid nitrogen boiling point), so I needed to put the sample in thermal contact ...
0
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0answers
16 views

The distribution of net charge in the Millikan oil drop experiment?

What is the distribution? Of course it depends on the concrete setup. But, what is the typical value? The concern is that, if the distribution is peaked at, say 1000, it would be very difficult ...
0
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0answers
21 views

LIGO Gravitational Wave Discovery and Gravitons [duplicate]

Now that gravitational waves have been detected, how hard will it be to detect a graviton? Will the equipment have to be more sensitive or are the difficulties more complicated than that?
3
votes
2answers
72 views

Best way of calculating average acceleration in lab experiments

I am doing a lab experiment that works as follows. An object moves along the $x$ axis with an initial acceleration and then moves with a pretty constant velocity that may slightly vary within $20\%$ (...
4
votes
1answer
1k views

Best way to move teaspoon to dissolve sugar in a cup of tea

I know that there is asked questions about something like cooling down cope of coffee..etc, but this one is little different. My friend was watching TV program of English eating etiquette, and they ...
0
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0answers
32 views

What is space charge Capacitance of diode?

Most of the books say that $p$-type and $n$-type materials of diode act as parallel plates of space charge capacitance were as the depletion charges (uncovered) act as dielectric. Then why do these ...
0
votes
1answer
47 views

Propagation error for a third grade equation

I am trying to find the value for the roots$\pm$error for a set of experimental data. The function that fit the best is $$\epsilon(t)=a+bt+ct^2+dt^3.$$ Which is the best way to calculate the roots $\...
0
votes
1answer
21 views

Why characteristics graph of Geiger Muller Counter always goes up?

The characteristics graph of Geiger Muller Counter always keeps going up and does not drop down . It may remain constant over an interval but does not drop down on the graph scale. Why it does not ...
0
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0answers
20 views

Classification of experimentally-determined physics laws? [duplicate]

Has anyone classified (or attempted to classify) all the experimentally-determined laws of physics, such as with a simple diagram or even in a full-length book?
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2answers
164 views

Why is it that the refrigerators (ice houses) from long ago can't be reconstructed in modern times? [closed]

A Long time ago (a couple of hundreds of years), people could make a refrigerator by applying a certain procedure with pieces of ice, harvested in winter, and other stuff. The ice hadn´t molten at the ...