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age 54
visits member for 2 years, 4 months
seen 3 hours ago

BEE 1992, MEE 2001, PhD in progress

Starting building Heathkits in early 70s. Consumer electronics tech through 80s. EE since then. Sold company in 00s. Teach EE classes on occasion now.


4h
comment How does a phonon cause two electrons to attract each other and form a cooper pair?
@Danu, I understand your concern, however, my interests are elsewhere for now. I will consider expanding a little in time.
5h
comment How is time real?
This question appears to be off-topic because it is about metaphysics.
5h
comment How is time real?
"there's no time, only physical and chemical reactions which strive to react with each other". If you pause and think clearly about this, you'll find that you've smuggled in the notion of time with such notions as "reactions" and "strive to react". One cannot coherently deny the existence of time with arguments that genetically depend on the existence of time.
5h
comment How is time real?
"Isn't time a human created concept?" Which concepts aren't human created (as far as we know)?
6h
answered Negative charge on capacitor, Kirchoff differential equation with step function
7h
reviewed Approve suggested edit on Rotational Inertia of Two rods
10h
comment Setting the peak or peak to peak output voltage
I sympathize with that position @Mostafa but it's a fuzzy line due to the ubiquity of electronic test and measurement equipment in experimental physics.
11h
comment Finding angular accleration
Some kinds of questions should not be asked here: "Do my homework"-type physics questions, e.g., "A 4kg ball is traveling at 8m/s in the x direction, how do I find..." physics.stackexchange.com/help/on-topic
13h
comment Can two electrons have the same momentum and spin directions?
In words, a particle with a definite momentum is not located (or more precisely, localized) anywhere. Put another way, the 'spread' in location is inversely proportional to the 'spread' in momentum. Localizing momentum (position) necessarily means delocalizing position (momentum).
1d
comment Quantum mechanics: Finite square well problem
Actually, we require that the energy eigenvalue be greater than the minimum of the potential energy (otherwise the solution is not normalizable). In your example, the energy eigenstate will be a bound state if the associated energy eigenvalue is greater than -10eV and less than the potential energy at infinity.
1d
comment Is superposition principle equally valid for both scalar and vector quantities?
@BenCrowell, correct but, as in, e.g., Fourier analysis, we can write the solution as a linear superposition of weighted basis functions. I concur that non-linear vector valued equations do not allow superposition of solutions to make another solution but it isn't (wasn't?) clear to me if this is Swami's question or not.
2d
awarded  newtonian-gravity
2d
comment Is superposition principle equally valid for both scalar and vector quantities?
I might be way off base here but, as far as I know, vectors live in a vector space and, by definition, a vector space is linear. See a related question here: math.stackexchange.com/q/479095
2d
comment Calculate the flux of a point charge with Gauss's law
I think that Gauss' law is specifically about closed surfaces (such that there is a clearly defined volume and charge enclosed), i.e., surfaces with zero boundary. Though your approach can be made to work, keep in mind that there are an infinity of surfaces bounded by a circle. Given that degree of freedom, shouldn't you choose a surface that is normal to the field lines? hyperphysics.phy-astr.gsu.edu/hbase/electric/gaulaw.html
2d
comment Atom in a box and collapse of the wave-function
Certainly, you can say that, at some event, the atom emitted a photon of a particular energy which interacted with the film at a particular position. Thus, you know that shortly after that event, the atom had less energy than before. Since it most likely took some time to develop the film and, since the box is transparent, I don't think you can say much more than that.
2d
comment Interaction pictures of Quantum Mechanics
Related: physics.stackexchange.com/questions/45455/…
2d
answered Why is $\pi$ used when calculating the value of $g$ in pendulum motion?
2d
comment Having trouble understanding some stuff about delta functions
14 seconds apart!
2d
answered Having trouble understanding some stuff about delta functions
2d
comment Calculate the density of this liquid and determine general formula for finding density of a liquid
Some kinds of questions should not be asked here: "Do my homework"-type physics questions, e.g., "A 4kg ball is traveling at 8m/s in the x direction, how do I find..." physics.stackexchange.com/help/on-topic