42,510 reputation
458136
bio website inspirehep.net/…
location Duchy of Grand Fenwick
age 44
visits member for 4 years, 9 months
seen 9 hours ago

Experimental nuclear and particle physicist. These days I'm teaching, but I've spent a lot of time on nucleon structure in fixed target electron scattering and neutrino oscillations using reactors and beam sources.

Been reading Zemansky & Dittman's book on thermodynamics recently. Quote: ``The concept of temperature is rich in interpretations and levels of abstraction.'' Nice.


13h
comment How can we explain the difference in change of kinetic energy, due to different frames of reference?
These things are true, but they don't answer the questions about how to reconcile the difference in the resulting $\Delta \mathrm{KE}$.
14h
comment Decay of excited electron from Schrödinger equation?
I'm pretty sure you have to add a external Hamiltonian contribution by hand or assume the electron starts in a mixture of time-independent eigenstates. If you assume the electron starts in a pure time-independent eigenstate and there is no perturbing component in the Hamiltonian, then you get time-independent behavior.
18h
comment Do relativistic electrons have more charge?
Pay attention to the "closed surface" requirement...
22h
comment Why does a sheet of paper fall slower than the same when rolled into a ball?
Additional thing to try: lay the paper flat on top of a heavy book that is slightly larger than the paper and drop them together.
1d
comment Why teachers use red ink for checking, why are traffic signals show red for stop?
Automated posting bans are a feature of Stack Exchange sites designed as a defense against users who seem to be providing large amounts of poor content and thereby threatening to dilute the high quality of the sites. The details of the algorithms used to decide these blocks are not public, but the message you received when your attempt to post was blocked included a link. Read it. Carefully.
1d
comment It is possible to have a situiation in which $|\mathrm{d}v/\mathrm{d}t|$ is not zero but $\mathrm{d}|v|/\mathrm{d}t$ is?
I'd swear we had another question with this exact title just a month ago. Here we go: physics.stackexchange.com/questions/196699/…
1d
comment Why don't lakes have tides?
The point is that the tidal forcing drives resonance in bodies of water, and that causes there to be high and low spots in the surface which have the right period, but are, in general, out of phase; further their size depends on the $Q$ of the resonance rather than directly on the strength of the tidal interaction.
2d
comment What is Drake equation?
"The Drake Equation is a way of predicting how many [...]." (emphasis mine) A less charitable phrase would be "justifying a wild-ass-guess about". Not that there is anything wrong with the process (though the particular factorization into terms in necessarily arbitrary), just that this thing has never had anything like a rigorous use, and won't until we have so much statistical data about biological processes that we'll already know the actual answer.
2d
comment What produces this 477 keV spectral line?
Beyrillium-7 is pretty exotic and can be made in cosmogenic processes, but the rate is tiny (events per square-cm per year...). It worth taking the lines you are confident that you have identified and checking the energy calibration of the device. My experience suggests that a fairly modest miscalibration in energy can lead to unnecessary struggles in identifying lines.
2d
comment Quark model in particle physics
It might be helpful to clarify that a tetraquark is $qq\bar{q}\bar{q}$ and a pentaquark $qqqq\bar{q}$.
2d
answered Does work done require interaction between system and surrounding?
2d
comment Kinematics-Motion in one Dimension
Like most plain kinematics problems this is mostly an exercise in algebra.
2d
comment Is it possible to determine the velocity of electron in its orbit?
An bound electron doesn't have a velocity because it is not in "orbit". It's a quantum object and it forms a bound state identified with an "orbital" and those words do not mean the same thing. The Rutherford/Bohr picture may be intuitively appealing but it is more wrong than right. What @JahanClaes suggests is at least defined, but you shouldn't think of that as giving an "orbital velocity".
2d
comment How to let pythia to output the complete event record in LHEF or StDHep format?
I'm afraid we don't have much expertise on Phythia, and most questions about it go unanswered or unhelpfully answered..
Aug
26
comment Why does the superposition principle work in method of images?
Hmmm ... it seems I misunderstood the question.
Aug
26
awarded  Nice Answer
Aug
25
comment Object pursuing exactly toward an uniformly moving object, with a twist
Note that just posting your effort is not enough to make homework (and homework-like) question on topic. See meta.physics.stackexchange.com/questions/714 for discussion. Questions need to have value beyond just answer are particular exercise, and this is achieved by asking about physics.
Aug
25
revised Hydrogen Spectra using Hydrogen Gas Discharge Tube
edited tags
Aug
25
comment Hydrogen Spectra using Hydrogen Gas Discharge Tube
If your tube is of commercial manufacture, get and check the data sheet for safe voltage levels.
Aug
25
comment If heat can't be transformed into other forms of entropy, why do hot things radiate electromagnetic waves?
The second law of thermodynamics ranks right up there with relativity and quantum mechanics in the "most misunderstood" sweepstakes. And almost every attempt to construct a pop-sci statement makes things worse, not better. The version that you have (or think you have here) is badly mangled and completely incorrect.