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1. A Change of ε with pressure for Semiconductors

In "Sado Adachi" book "Properties of Group-IV, III–V and II–VI Semiconductors" page 222, he reported that "both εs and ε∞ decrease almost linearly with increasing pressure", however i was not able to find any empirical formula to describe these relationship for materials InAs, InP, InSb, where...

Thanks :)
3. Revisiting Newton's Second Law

I wonder why newton second law, define force as mass x acceleration, acceleration is the second time derivative of displacement, why he didn't define the force as mass x higher order time derivatives of displacement
4. I From Non Hermitian to Hermitian Matrix

Is there any way that i can convert a non-hermitian matrix to a hermitian matrix ?
5. I Spiral Equation

thank you for your interest in the question, i was not quite clear in stating the problem, by family of curves i mean a family curves that all intersect at one single point, and they are identical such that you can have them all by rotating one of them around an axis at the point of...
6. I Spiral Equation

I am looking for a family of curves where if we consider one curve of them and get the tangent of that curve at any arbitrary point on the curve, then you will always find a point in the other curves where the tangent of this point is perpendicular to the tangent of the first point. My guess...
7. I Great Circle Distance Derivation

I want to convince myself that this formula (ds)2= R2 [ (dθ)2 + sin2θ (dφ)2 ] is true
8. I Great Circle Distance Derivation

I derived the shortest distance between two points on a spherical surface (Great Circle Distance) , using the definition of the spherical coordinates and the dot product of the position vectors r1 and r2 where r1 = ( R cosθ1 cosφ1 , R cosθ1 sinφ1 , R sinθ1 ) r2 = ( R cosθ2 cosφ2 , R cosθ2 sinφ2...
9. Relativistic Calculations for De-Broglie Wavelength

As far as i understand, there is nothing in the first approach states that the De-Broglie wavelength depend in anything but the momentum in the first approach i replaced the momentum by the kinetic energy, and this is a valid replacement please explain your point
10. Relativistic Calculations for De-Broglie Wavelength

Homework Statement At what energy will a non-relativistic calculation of the De Broglie wavelength of an electron be in error by 5%? What is this energy for a proton? Comment on your results. Homework Equations I have two (seemed to be) logical answers for this question, but with different...
11. Conditions in Wave Function, and Integration

I want to know how this integral will equal zero? I know that Ψ will fall to zero as x goes to infinity and i know that Ψ must fall to zero very quickly , Ψ must fall to zero faster than 1/√|x| all of this will help evaluating this integral i tried to solve it as follows The first term...
12. Transformers and iron cores and frequency

What about the frequency of the secondary voltage? it will increase?
13. Transformers and iron cores and frequency

As far as i understand the thing that matter in all of the process of mutual inductance is the rate of change of the current in the primary coil $$\frac{dI}{dt}$$ butting soft iron core will increase the density of the magnetic field inside the primary coil, but how this will effect...
14. Relaxation time approximation and ideal hydrodynamics

unfortunetly there is nothing more
15. Relaxation time approximation and ideal hydrodynamics

Homework Statement please check attachment Homework Equations please check attachment The Attempt at a Solution since the deviation from f_0 to f is linear then we can write f=f_0 + C where C is some constant this should be enough to prove the first question (i think so) for the second...
16. Are Bathroom Scales geocentric?

i need to be sure of that, for example i want to know if gold scale manufacturers puts a label on their products that they are suitable to be used in london not in Kenya :) don't worry, i will not try to go to sell gold to people in the north pole :)
17. Are Bathroom Scales geocentric?

So i can say that "for scales that is used to measure very valuable materials, or some scientific computing, they must design scales that takes into account earth rotation and where on earth we will use these scales, so now i can say that a scale made in london will not be suitable to be used in...
18. Are Bathroom Scales geocentric?

so the answer that no manufacturer make these bathrooms to be fit in one place london for example (geocentric) , all bathroom scales are for global use everywhere in the earth HallsofIvy : your comment is very true, sorry that i didn't notice that , thanks :)
19. Are Bathroom Scales geocentric?

i know that bathroom scales measures the normal force, hence the equivalence mass but if we took earth rotation into account then the normal force will be less by a value mv2/R according to this relation N = mg -mv2/R Example : a 70 kg man standing on a bathroom scale on the equator ...
20. Asymptotically stable node

Is there a visualizations for the critical points somewhere in the internet?
21. Asymptotically stable node

to be more specific, i need real world examples of a sink node , and a source node
22. Asymptotically stable node

Hi, i need a real world example of an asymptotically stable node, is there such a thing as asymptotically unstable node?
23. Uncertainty equal to zero

for me the concept of infinite precision = the concept of infinity you could always try but you can never reach to an end
24. Uncertainty equal to zero

i understand that the uncertainty principle prevent us from doing a measurement with complete certainty for pairs of physical quantities (position and momentum) (energy and time) and that there is some kind of trade off in the uncertainty of the measurement for each quantity of them Ok, now...
25. Uncertainty equal to zero

it is like you are saying that mathematically it is possible to measure the momentum with zero uncertainty , but in physics this is impossible saying that the free particle is never exist is much like saying that nature refuse a complete certainty for a measurement of the momentum or the...
26. Uncertainty equal to zero

But this will mean that the particle has a single value of velocity, there is no distribution whatsoever of this velocity, this would be a particle that has a single value of momentum or in the wave aspect a plane wave that fills the whole universe, a particle that exist by the same probability...
27. Uncertainty equal to zero

yes the wording wasn't clear it should be like that "The bottom line is, we can't do a measurement for velocity with zero uncertainty"
28. Uncertainty equal to zero

that is means that, there have to be some uncertainty (not equal to zero and not equal to infinity) in the position to measure some uncertainty (not equal to zero and not equal to infinity) in velocity and the bottom line is that we can't be have a measurement for velocity with zero...
29. Uncertainty equal to zero

could we able to measure the velocity for a free particle with uncertainty equal to zero, could we able to have a certain values for its velocity, and let the uncertainty of the position to be infinity is there any theoretical restrictions on having a certain value for the velocity? is there...
30. Phase portrait for a conservative negative potential

it was like drawing the hyperbola as y=f(x) so it becomes symmetric around the y-axis for the first group of hyperbolas, then drawing it as x=f(y) so it is symmetric around the x-axis for the second group of hyperbolas.