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0answers
36 views

What experiments of a high school standard are there to investigate the magnetoelastic effect?

I've ended up investigating the reverse magnetostrictive effect for coursework, which is 30% of my grade this year. I started by hitting a magnet with a hammer (on the recommendation of my teacher) , ...
0
votes
0answers
54 views

Good book for learning about mathematical foundation of quantum physics [duplicate]

I've been trying to slog through Quantum Physics for Dummies, but can't even get past the first chapter. There's a lot of talk of Bras, Kets, and Hilbert spaces, but I feel I'm missing the ...
0
votes
1answer
29 views

Why is conductivity isotropic in a plane perpendicular to the z-axis of a tetragonal crystal?

Considering the symmetry of a tetragonal crystal, how can it be proved that conductivity is isotropic in a plane perpendicular to the z-axis?
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0answers
40 views

Heat sink simulation with a fan

I am trying to solve this problem using advection-diffusion model and finite element method for solving it due to the complex geometry. Basically the problem i'm trying to solve using OpenFOAM is see ...
0
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0answers
13 views

Force on a small conductor in an EM wave

What forces act on a small, flat conductor subjected to electromagnetic radiation, if the conductor is much smaller than the wavelength? My guess is that the magnetic field component of the wave ...
0
votes
0answers
14 views

How do I derive Sommerfeld's solution of the case when the incident ray is aimed obliquely to the edge of the screen?

I already know that the Sommerfeld's solution to this problem is conical. But internet does not show me the simple of exact derivation of this solution. How do I solve this problem?
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votes
0answers
23 views

Which factors are most important for choosing the optimal working fluid in a Stirling engine?

The theoretical factors I can think of are heat capacity, thermal conductivity, and viscosity. It seems to me that helium should be the better than hydrogen since it has lower heat capacity but also ...
0
votes
0answers
48 views

Polarization modulation

To increase bandwidth, for EM free space communication, could you modulate the polarization, so that, e.g., for a one-meter wavelength radio wave, the polarization could be modulated between vertical ...
0
votes
0answers
42 views

What is a simple example of band structure having varying “orbital character”?

I'm trying to understand exactly what orbital character is in the band structure of a solid, such as that described in this paper and many others. I'm having trouble finding references online that ...
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0answers
37 views

Insulation for magnetic fields [duplicate]

How can I insulate conductors independently one off the other, where they pass through a magnetic field? Are there a techniques or alloys? There is a issue how to insulate copper wire where current ...
0
votes
1answer
19 views

Two-linkage under the force and friction

I need to find friction force in this configuration. Book says that $F_{fr}=\mu P.$ but i think that force $P$ is distributes evenly between hinge (A) and sliding block (B), so friction must be $1/2 ...
0
votes
1answer
91 views

What does the equation of a refracted ray trace mean?

I am doing a ray trace to a refracted vector. I read in some PDF files that: vector($\mathbf{t}$) is the refracted ray, vector($\mathbf{i}$) is the incident ray, the angle $\theta_t$ is the refraction ...
0
votes
1answer
92 views

A question about first order perturbation in the Stark effect.

Consider ground state of a hydrogen atom which influenced with external uniform weak electric field. What does mean the following statement? $$\left< 100|\quad Z\quad |100 \right> =\int { |{ ...
0
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0answers
54 views

Density functional theory and partial charge transfer

When density functional theory is used to simulate a molecule adsorbed on a surface, it turns out that due to their interaction, a fraction of an electron is transferred from the surface to the ...
0
votes
1answer
59 views

Motional emf and ohm's law

Suppose a thin, closed loop of wire is in motion in a static magnetic field. Let's define a few things $$\vec{F_B} = \vec{w}\times\vec{B}$$ $$\Phi = \int_S \vec{B}.\vec{dS}$$ ...
0
votes
0answers
59 views

Lattice structure, Debye-Scherrer-Method

My question is: How can I find out what kind of lattice structure I have, with simply using the Debye-Scherrer method? One part of my exercise was to calculate the static structure factor for a fcc ...
0
votes
0answers
38 views

Tricky question (physics) [duplicate]

I know this may not be the place for this question, by stackexchange physics has banned homework questions :( A piece of hair taken from a goat has a radius of $3.1\times 10^{-5}\text{ m}$. What ...
0
votes
1answer
24 views

Why do electrons on the surfaces of a lens focus photons instead of scattering them in all directions?

Compton tells us electrons on the surface of a lens should scatter photons, not focus them. Imagine a photon traveling from a pinpoint on the surface of a source object to a silicon atom on a lens ...
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0answers
14 views

Tight bounds between maximum weight and precision

Scales are rated according to their precision and maximum load -- attributes which seem to be universally close to one another (within about 3x10^4 grams). Eg, a scale that can measure up to a ...
0
votes
1answer
91 views

How does the net torque have to be 0 at all points for static equilibrium? [duplicate]

I know that for a mass to be in static equilibrium two things have to be satisfied: $\sum F=0$ and $\sum T=0$, where $T$ represents torque. However, I am not sure how the latter can apply in a ...
0
votes
0answers
22 views

A good textbook on Introduction to Quantum Mechanics? [duplicate]

I'm starting my master in Physics. I've taken some Quantum classes before, but nothing as serious as this. I would like now to really go in detail with all the concepts of QM. My professor recommended ...
0
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0answers
45 views

Probe/Sensor-design for pulsed electromagnetic field

So I have a wire/coil, acting as a sender, which has a pulsed signal as described below. I would like to build a sensor/probe that can detect the electric field at a distance, where the primary goal ...
0
votes
1answer
281 views

Magnetic fields in transformers and back emf?

i am having some trouble with understanding the magnetic fields inside transformers and how they relate to back emf. My first query is: is the magnetic field produced inside the soft iron core ...
0
votes
0answers
79 views

How to formulate pin joints in finite element modeling of solid frames

In frame analysis with finite element every node can be assumed with 6 Degree of Freedom (3 translation DoF and 3 rotational DoF). There are formulations over the web for creating stiffness matrix ...
0
votes
1answer
141 views

magnetic field of a rotating ring magnet

Can the magnetic field of a rotating ring magnet induce current in a conductor? Is there a flux linkage between magnetic field of a rotating ring magnet and a conductor?
0
votes
1answer
37 views

How did the author derive the distance the particle takes as $\dfrac{h}{cos\theta}$?

On Page 292 of Griffith's Introduction to Electromagnetism (3rd ed.) he mentions that the a basic for of a generator is one in which one pulls a square wire with one side of it in an uniform magnetic ...
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0answers
53 views

Hamiltonian of a linear chain of atoms and canonical quantization

When we want to re-formalize the Hamiltonian of a linear chain of atoms which has the following form: , we define the ladder operators as: and we use the following relations: to show that we ...
0
votes
1answer
26 views

phase transition and effect on leptogenesis

What is the effect on leptogenesis in the standard model if the electroweak phase transition is (i) first order and (ii) second order?
0
votes
0answers
27 views

Help Interpreting Ultraviolet Photoelectron Spectroscopy (UPS) data

I was given a batch of UPS data without any background other than the materials examined and I don't have any experiencing interpreting it. I wanted to reach out to some experts (hopefully, someone ...
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votes
0answers
26 views

Regarding Chebychev and Gravity

I recently learned Chebyshev's Inequality (in statistics). He uses the inverse square to specify an upper bound to the proportion of entities of a set as it recedes on either side of the mean. I am ...
0
votes
0answers
36 views

Literature on semiconductor modeling

Analysis and Simulation of Semiconductor Devices by Selberherr (Amazon link) seems to be the book on the basics of the craft, yet it was written in 1984. Are there any more recent books or have the ...
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0answers
22 views

which data and experiment prove mirror symmetry

refer from the book by David A Cox, Mirror Symmetry and Algebraic Geometry how to demonstrate supersymmetry eliminate the difficulties of string theories how to use data to show eigenspace (p,q) = ...
0
votes
0answers
28 views

Obtaining angular velocity of a general orbit

Provided you are given a effective potential function i.e. $$ V_{eff}=\dfrac{J^2}{2ml^2sin^2(\theta)} + mgl(1-cos(\theta))$$ how do you obtain the angular velocity for different types of orbits; i.e. ...
0
votes
0answers
12 views

magnetization of a infinite crystal lattice

Cosider a infinite crystal lattice with right face end at infinity and left face end at origin.my question is, consider this crystal is made of material which can be magnetized and if you magnetize ...
0
votes
2answers
82 views

Pair production and energy conservation?

Consider the question whether a photon can decay, in the free space, into an electron and a positron - a pair production event. Such an event I don't think is possible, because both energy and ...
0
votes
1answer
72 views

Eigenvalue of Hamiltonian under gauge transform of Bloch state

$H = \sum_{k} V(q) a_{k4}^{\dagger}b_{k3}^{\dagger}b_{k2}a_{k1}$ where $q$ is the transfer momentum, $a$ $b$ are two orbits or two sublattice sites. Will the eigenvalues of the above Hamiltonian ...
0
votes
0answers
30 views

A question about the interchanges of particles belonging to species in Weinberg's QFT book 1

Weinberg put this in page 171 that I can't quite understand: If we like, we can avoid this question by simply agreeing from the beginning to label the state-vector by listing all photon momenta and ...
0
votes
0answers
70 views

Are Laplace Operator and mean curvature exactly the same thing for 2D function?

Let's assume we study 2D function/surface f(x,y). Then Laplace Operator is defined as: $$\nabla^2 f=\frac{\partial^2f}{\partial x^2}+\frac{\partial^2f}{\partial y^2}$$ And the mean curvature: let ...
0
votes
0answers
52 views

Bopp operators and Wigner-Weyl representation

I am learning about the Wigner-Weyl transformations to move a c-number Lindblad operator A(x,p) back into operator form. As far as I know, to move back and forth normally requires a four variable ...
0
votes
0answers
30 views

on what factors time depends physics [duplicate]

On what factors the "Time" depends? In time dilation experiments we use a light clock in which a pulse of light moves up and down between two mirrors. We derive that, for a person in movement, his/her ...
0
votes
0answers
95 views

Upper limit on the size of the “unobservable” universe based on surface area divided by Planck constant?

There are many kinds of size scale to the universe one can talk of. Much has been discussed with the concept of the upper limit of "bits" contained in the observable universe and therefore the total ...
0
votes
0answers
25 views

Average value of function [duplicate]

Can anyone help me in solving Q .1 & .2? Also I am confused at one point. In $F(x+p)$ where $p$ is period. It means that the function is at the point period plus $x$ dist. Away.So how can I put ...
0
votes
0answers
15 views

Find center of mass and moment applied on beam structure. [duplicate]

I have a simple mathematical problem to solve but it is giving me a slightly difficult time to figure out. The problem: I have a beam structure with same cross section. It consists of three beam. ...
0
votes
0answers
26 views

Why is permittivity or permittivity negative in certain metamaterials?

I read some papers and I think the explanation is that the driving electric (magnetic) field leads the response by π, thus making the effective permittivity (permeability) negative. But my question ...
0
votes
0answers
31 views

Why Does Electron Revolve around nucleus? [duplicate]

Actually why does electron revolve around nucleus. Considering Simple atom, hydrogen atom where a single electron revolves around the nucleus. It is said that the electrostatic force of attraction ...
0
votes
0answers
43 views

Simple math used for physics

I read the book "Analysis 1" by Harro Heuser about calculus and it several interesting chapters about applications of mathematics for physics. For example there was one part of the chapter, which ...
0
votes
0answers
95 views

Instantaneous acceleration in non uniform circular motion

How is instantaneous acceleration different from tangential acceleration in a non uniform circular motion? We know that instantaneous acceleration is tangent to a point at any given time and so is ...
0
votes
0answers
101 views

Decreasing Temperature and Pressure of a closed system

I have a closed system that contains a pocket of gas. What happens to the volume of the gas when the ambient pressure acting on the system decreases, and the internal energy of the system decreases. ...
0
votes
0answers
56 views

Electric and Magnetic Field Created by Moving Electron

From a classical perspective, what are the electric and magnetic fields created by a single electron, initially located at the origin and moving along the $x$ axis with velocity $v \ll c$? I'm ...
0
votes
0answers
75 views

Photoelectric-effect laser

The question is whether it is physically possible to build a laser using only the photoelectric effect in the vacuum, with no lasing material. I know that there is a whole history of laser ...

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