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A text says:
An X - ray diffraction experiment is carried out on a crystalline solid having FCC structure at room temperature. The solid undergoes a phase transformation on cooling and shows orthorhombic structure with small decrease in its unit cell lengths as compared to the FCC unit cell lengths. As a result the 31... |
I am reading Special Relativity for Beginners, by Jurgen Freund, and Chapter 12 is on Accelerated Motion. I am having a difficulty with a basic integral laid out in there.
The equation of the x-component of acceleration when converting from the primed frame to the unprimed frame (primed frame has only relative velocity... |
I have found that this happens through anodic oxidation, but can't seem to find how this happens. Why do some metals form an insulating layer when in contact with an electrolyte?
|
Might be the question is not up to the mark and caused due to some misunderstanding. Please still give me the idea where I was wrong.
I am studying quantum mechanics and came across the fact that we can use the Fourier transforms to define the wavefunction in momentum space.
What caught my attention was that the moment... |
Is it possible to create two objects that are the same on the molecular level?
By two objects, I mean two different objects that have the same label.
For example, can you create two different breads that have the same molecular structure? How do we know that they don't?
Are all iPhones 8 structured molecularly the same... |
Are there any materials which could effectively insulate against convection (and/or conduction), that don't insulate against radiation?
Specifically, I want to make a water-heater that uses solar energy. I could run tubing up and down through a box, and provide a glass cover, which would effectively allow radiation to ... |
From the detection of gravitational waves in GW190814, the merging of a 2.6 solar mass compact object with a heavier object has been inferred. The lighter object is in the "mass gap" between the heaviest neutron stars and the lightest stellar mass black holes, making astrophysicists wonder what kind of an object this w... |
When we say that the universe is flat, this means that the sum of angles of any triangle will always be 180°.
I believe that "flat" refers to the bending of spacetime in a 5-dimensional space (or a forth space dimension). This would however contradict the fact of the su of angles, as for warped space, the sum is smalle... |
In the context of quantum gravity, but also in other places, I have heard the question "does this effective field theory admit an UV completion?". However, I really don't understand this question, in the following sense.
It is my understanding that an effective field theory is a field theory that is valid at low energi... |
Wikipedia states,
"In physics, two wave sources are perfectly coherent if their frequency and waveform are identical and their phase difference is constant"
In an A Level Physics Marking Scheme, students are often asked to define coherence. The mark is scored for saying coherence is when the waves 'have a constant / ... |
How would you explain
electrostatic potential,
electrostatic potential energy,
electrostatic potential difference, electrostatic potential gradient and common potential
What is the difference between them?
|
I am following an introductory course on General Relativity based on the work of Sean Carroll in: Spacetime and Geometry.
After a lot of trouble we get to the following differential equation:
$$\frac{d ^2 x^\mu}{d \lambda ^2}+\Gamma ^{\mu}_{\rho \sigma}\frac{dx^\rho}{d\lambda}\frac{dx^\sigma}{d\lambda}=0 \ \ \ \ \ \ \ ... |
Charon is so massive relative to Pluto that they both orbit a point that is outside Pluto. The distance from the center of Pluto to the barycenter is given by:
$$r = \frac{a}{1+\frac{m_{pluto}}{m_{charon}}}$$
where
$a$ is the distance between the centers of the two bodies,
$r$ is the distance from the center of the p... |
While computing the Chern number of electronic wave functions
\begin{align}
\left|\psi\right\rangle = \begin{pmatrix}\cos\left(\frac{\theta}{2}\right) \\ \sin\left(\frac{\theta}{2}\right)e^{i \phi} \end{pmatrix}
\end{align}
on the Bloch Sphere ($S^2$), it turns out that the wave function has singular dependence (vorte... |
In Lagrangian mechanics, when talking about a particle position expressed in generalized coordinates it is usual to find the expression:
$$\mathbf{r}(q_0,...,q_k,t)\tag{1}$$
what it means this isolated $t$ time variable?
Wikipedia uses the expression (see here):
$$\mathbf{r}(\mathbf{q}(t))\tag{2}$$
I can understand all... |
I'm wondering about the situation where you have two orthonormal wave functions,
$$ \langle \varphi( \vec{r_1}) | \psi ( \vec{r_2}) \rangle = 0 .$$
Under what restrictions would a coordinate transformation of one of the states, $ \vec{r_2} \rightarrow \vec{r_2}+ \vec{R},$ preserve orthogonality?
$$ \langle \varphi( \v... |
This occurred to me when making an omelet. I want to construct a 3-dimensional rigid egg that when placed stationary on a flat surface with no friction or slipping either rolls to an unbounded distance or has a non-periodic trajectory.
Solids of revolution do not work because by symmetry the torque vector and the axis... |
From Wikipedia on how to create a tesseract:
0 – A point is a hypercube of dimension zero.
1 – If one moves this point one unit length, it will sweep out a line segment, which is a unit hypercube of dimension one.
2 – If one moves this line segment its length in a perpendicular direction from itself; it sweeps out... |
I'm learning about ideal and non-ideal gas behavior in Chemistry, and my textbook and online sources say two things :
Gases behave ideally at high temperatures and low pressures.
Gases behave non-ideally at high pressures and low temperatures.
My question is : Doesn't increasing temperature lead to higher pressure (a... |
While solving a problem on hydro statics subject I saw a statement that argued that if I know the weight of the object in the air and then I know the weight of the object in the water.so when I subtract between the weight I can conclude the volume of the objects.
I have numeric example:
weight in air is $740 gm$
weight... |
If I have to combine 2 spin $\frac{1}{2}$ particles I do with Clebsch Gordan coefficients so that for example $|{\frac{1}{2},\frac{1}{2}}\rangle|{\frac{1}{2},\frac{-1}{2}}\rangle=\frac{1}{\sqrt{2}}(|{1,0}\rangle+|{0,0}\rangle)$. Now if I have to calculate C-G coefficients for this new state and another state for exampl... |
I know that if an object has a higher orbit, it will orbit at a lower speed. However, I don't know what the exact relationship is. Is the decrease in speed linear, or quadratic, or something else?
Also, as a bonus question: higher orbits not only have the objects moving slower, but they also have a larger distance to c... |
I don't understand what makes the Planck Temperature the "absolute hot". To my understanding Temperature is just a measure of the kinetic energy of the particles, so is the Planck Temperature the temperature at which the particles are moving at a speed so close to the speed of light that their behavior can no longer be... |
“If an underwater bubble is collapsed by loud sound, light is produced and no one knows why” says one of those click-bait social media posts with no citation—“light produced” and “no one knows why.” Is either true?
Not something I heard during my studies of underwater acoustics—but then, we weren’t very concerned with... |
I am trying to understand the second line of (7.40), which I've written below.
$$
\begin{align}\langle \alpha|\alpha\rangle &= c_\alpha h^{n(\alpha)}[1 + O(1/h)]\\
\langle \alpha | \beta \rangle &= O(h^{(n(\alpha) + n(\beta))/2 - 1}) + \cdots
\end{align}$$
where $|\alpha\rangle$ is a ''fixed length'' basis state of le... |
I am studying chapter 9 of Polyakov's ``Gauge Fields and Strings". The problem is to solve the path integral:
$$\mathcal{A}=\int \mathcal{D}X e^{-m\int _{0}^{1}d\tau \sqrt{-\dot{X}^2}}.$$
The domain of integration is the set of all curves in the target space $\mathcal{M}=\mathbb{R}^D$ with fixed boundaries $X_1$ and $X... |
This question came up while sharing a cup of coffee with a friend. I tried it out in my car on the way home, and it seemed to hang longer at some speeds than others. So, say I am driving straight at $50\ MPH$ then I let my foot off the gas and shift to neutral until I come to a complete stop. What speeds does the ca... |
Just as it says above... I cannot find a straight answer, and I have tried...
|
I want to know if there softwares to draw Feynman diagrams easily.
|
I noticed that Plutonium storage containers often have cc699 written on them.
A Google search for cc699 also brings up plutonium as the first page but I can't find any mention of cc699 on the page or anywhere else online.
What is the connection between cc699 and Plutonium?
|
Consider a bosonic system with time reversal symmetry $\mathcal{T}$ and a unitary on-site $\mathbb{Z}_2$ symmetry. Suppose the symmetry is realized in a special way such that $$\mathcal{T}^2= (-1)^B$$ acting on any physical local operator, where $B=0$ if the operator is $\mathbb{Z}_2$ even, and $B=1$ if the operator is... |
I am currently building a scanning photocurrent measurement setup. It basically focuses a CW laser down to $50\ um$ size on the sample and scan the laser beam over the sample (a metal) and record the generated dc current. I use a current preamplifier and a lock-in to detect the current with pA resolution (the chopper i... |
Is it correct to say that when a charge is at rest, it produces field and potential, or does it produce potential and because of the potential dfference, there is a field? Are both of these mathematical constructs for our understanding, or is there any other explanation for electric effects seen around charges?
|
In Lagrangian mechanics, I came across the notion of a point transformation which leaves the Lagrangian invariant. Normally it is denoted as follows.
$$Q = Q(q,t).$$
Now, unlike in the case of a canonical transformations (wherein there exist certain explicit conditions to check if a given transformation is canonical), ... |
I am not a physicist, but a fan of physics. I found many videos on YouTube which explain the "double slit experiment" but most of them use animation and that is OK. When I search for any real world experiments; I find only those experiments which show the "interference pattern", but do not find any real world experimen... |
As an example of the book "Introduction to Quantum Mechanics Schrodinger Equation and Path integral" by Harald J. W. Muller. We have to prove Liouville's theorem. Here I show the proof as the text presents it:
Show that $\triangle q \triangle p$ is independent of time $t$, which mean, this has the same value at >a tim... |
If we try to get closer and closer to a photon (i.e. get closer to speed of light), time slows down in a fashion similar to when we get closer and closer to a massive object. Are these two things related somehow?
Following up on this, can we say the following:
Normal matter -> bends both space and time
Photons -> bend... |
How can it be that both of the following are true for a series circuit:
If a resistor is replaced with another one of higher resistance, the current in the circuit decreases. If a resistor is added to a circuit, the current in the circuit decreases.
The current passing through a $1\Omega$ resistor in the circuit is t... |
Suppose I have a large home with two windows. Assume the home forms a perfect seal and does not leak fluid other than from open windows.
The window in the bottom of the home is open. The window on the top floor of the home is closed, with a fan pointed at it, blowing air at it. When I open the window in the top floor, ... |
Dears all,
I have the following exercise:
A sliding rod of length $b = 0.2 m$ is placed above two conducting rails connected to a voltage generator $V_0 = 6V$ (see fig). The rod has a resistance $R = 0.08 \Omega$ and is attached to a mass $m = 1.2 kg$ through a pulley. The entire system is exposed to a magnetic field p... |
If I integrate a dot product (e.g. $\vec E \cdot \mathrm d \vec s$), then the dot product itself becomes $|\vec E| |\mathrm d \vec s| \cos\theta $. But when I try to integrate the dot product itself, I can see now there is $|\mathrm d\vec s|$, not $ds$ (not a vector). Many books anyway treat $|\mathrm d\vec s|$ and $\m... |
My textbook mentions that the electric potential at distance of $R$ from a point charge $q$ will be given by $\dfrac{-q}{4\pi\varepsilon_0 R}$. I don't understand why the negative symbol appears here.
As I understand it, the electric potential there should be the amount of work that needs to be done by an external agen... |
I am looking for introductions and reviews (papers or books) on the possible observation and the nature of dark matter. This book seems to be a good start, but I would be grateful for any other recommendations that are accessible to people with knowledge of physics at the undergraduate level.
|
Is it possible that some nuclear decay that we think of as 'spontaneous' is actually catalyzed by an incoming neutrino?
I am imagining that there is some radioactive decay, let's just say a beta decay that appears to happen spontaneously:
$$ \rm ^n_mX \to {}^n_{m+1}X + e^- + \nu_e + \gamma $$
But it is actually cataly... |
I am reading a research paper (A Theoretical Analysis of Zero Field Splitting Parameters of Mn2+ Doped Diglycine Calcium Chloride Tetrahydrate) where they state the Hamiltonian term:
$$H=\frac{F}{180}\left\{35 S_{z}^{4}-30 S(S+1) S_{z}^{2}+25 S_{z}^{2}-6 S(S+1)+3 S^{2}(S+1)^{2}\right\}$$
I want to write this as a matri... |
In the figure given below is block placed on an incline $\theta$. Now the lift is accelerating upwards with an acceleration $a_0$. Now if we make our measurements from the lift frame we will have to apply a pseudo force $-ma_0$. Which will have two components one in the direction of $Mg\cos\theta$. And other in the dir... |
In vacuum, the $\vec{E}$ and $\vec{B}$ field are always perpendicular, in phase, and they travel at the speed of light $c=3\times 10^8 \text{m/s}$. I would like to know what happens in matter ? Do the same rules apply ?
|
If I have coupled system of two harmonic oscillators.
$$\ddot{x}_1+\Gamma\dot{x}_1+kx_1-kx_2=0$$
$$\ddot{x}_2+\Gamma\dot{x}_2+kx_2-kx_1=0.$$
Then I can fourier transform the equations of motion and get the Impedance matrix.
$$\begin{pmatrix} -\omega^2+i\Gamma\omega+k & -k\\ -k & -\omega^2+i\Gamma\omega+k \end{pmatrix}.... |
I think Sir Newton was aware of the serious flaw when he formulated the law of gravity. We all know time is an important component in doing science, but I don't remember that anyone tried to revise the equation to include time. I wonder why do we simply accept that the speed of gravitational force acting on an object i... |
I have some problems on understanding some semiconductors band diagram.
For instance, I understand quite well something like this:
I understand it because it is quite simple: there are the energy levels (Conduction, Fermi, Intrinsic Fermi and Valence) at right and left, and the transition region between them. Quite fi... |
I have a fluid flowing towards a sink such that its pressure distribution as a function of distance from the sink is given by
$$\frac{dp}{dx}=\frac{1}{x^2},$$
where $x$ is the distance from the sink and $p$ is the pressure.
The space around sink is spherically symmetric and hence $x$ represents spatial coordinates and ... |
Is the term $(\partial^{\mu}\phi)^{\dagger}$ same as $\partial^{\mu}\phi^{\dagger}$ for any complex scalar field $\phi$?
|
Suppose we are given the free-body diagram above, with a mass on an incline at an angle $\theta$. If my coordinate axes are taken to be the regular $x-y$ plane rotated an angle of $\theta$ (i.e. the x axis is parallel to the direction of $mg \sin \theta$ and the $y$ axis is parallel to $mg \cos \theta$), then if there... |
How would you calculate the total acceleration of a human body that is just starting to walk in the train against the direction of the train, who is also accelerating? Actually I want to have an evidence that the possibility to fall in a train while it is accelerating is higher, if you walk against the direction of the... |
In this Wikipedia article on zero field splitting, the Hamiltonian is defined as
$$H=SDS$$
where $S$ is the total spin $S_{1}+S_{2}$ and $D$ is the dipolar spin-spin interaction matrix. It is asserted that $D$ is diagonalizable and traceless. But why should it be so?
|
In the derivation for vis-viva equation
$$v^2 = GM \left({ 2 \over r} - {1 \over a}\right),$$
here they use specific quantities such as specific energy and specific angular momentum but I don't understand what value this provides.
Suppose you have only two bodies, then you will have only one mass 'factor' to multiply w... |
Consider an infinite long straight conducting wire with an oscillating current inside. The current is assumed to be uniform over the cross-section of the wire. The resistance per unit length is given by $$R_s=\frac{\rho}{A},$$ with $\rho$ the resistivity and $A$ the area of the cross-section of the wire.
The oscillatin... |
I have a semantic question about Bernoulli's equation,
I learned that Bernoulli's equation is: $$\frac{v^2}{2} + \frac{P}{\rho} +gy=const.$$
My question is why is it that at point $C$ the pressure is $$P_o - \rho gh $$ and not $$P_o + \rho gh ?$$
what is the meaning of the minus sign?
Consider $y=0$ as drawn in the pi... |
I'm struggling to see how $\langle x|\Psi\rangle =\Psi(x)$.
I have read a few previous bra ket questions in here but still not clear.
Any good book for understand the bra-ket notation in more rigorous way.
|
I am trying to calculate the amount of energy required to bring 1 litre of water up to boil (from 20 degrees C to 100 degrees C) and to maintain the water temperature at 100 degrees C for a period of 5 mins.
The end goal is to translate this into the theoretical amount of wood required to do so over an open fire using ... |
I wonder about following scenario: Given a pure liquid, let's assume oil but an ageing case. The case causes that impurities (water, gases,..) enter over time resulting in a more and more impure oil.
The goal is to collect all these impurities.
Let's call the case actually a tank which is, e.g., of 5x5x5m³.
I'm not tha... |
This is a full wave bridge rectifier:
The waveform of the full wave bridge rectifier is this :
But I want a more smooth signal which will remind less of an AC. If I put an inductor with a resistor instead of only a resistor will it work?
|
In theory, it is fairly simple to measure a qubit's state. Let us consider a Ramsey experiment, where the qubit is in the ground state $|0\rangle$ initially. Then by applying a Hadamard gate the qubit becomes a superposition state $|+\rangle = \frac{1}{\sqrt{2}}(|0\rangle+|1\rangle)$. After waiting for a while the stat... |
So, using the Dirac spinor notation for plane-wave electrons and positrons from HERE, and the definition of the adjoint of $\psi$ = $\psi^{*T} \gamma^0$, and applying that to the "up" electron (with the Dirac version of $\gamma^0$), I get
$\bar{\psi} = e^{ip\cdot x} [ 1 \space 0 \space -p_z/(E+m) \space \space (-p_x+ip... |
I am currently reading Practical Flow Cytometry, fourth edition, by Howard M. Shapiro. The author says the following when discussing scattering:
Scattering, which explains both reflection and refraction, typically involves a brief interaction between a photon and an electron, in which the photon is annihilated, transf... |
I'm new to physics and trying to understand Newton's second law $F = ma$ but I don't think I'm grasping the concept of force very well. I've read other questions and answers on this law and it is my understanding, for now, that $F = ma$ is a "definition" of force based on the empirical "law" that the product $m \times ... |
If you have two blocks with masses $m $ and $M$, all surfaces being frictionless, and you give a sharp impulse to say, the upper block with mass $m$, so that it has a velocity $v$, will the lower block also start moving?
I've seen many problems which ask for the velocity of the lower block, but I don't see how it could... |
Why are so many fundamental physical laws expressed in terms of integer powers of some quantities? I'd expect this to be a very, very unlikely occorrance, since the Nature doesn't know that "we count by fingers".
|
I've been staring at this problem for quite sometime, but I don't think I understand bra-ket notation in the form $<a | x | a>$. I understand that <a|x> is just an inner product, but I suppose I'm a little confused once we add in that third term. Could someone break this down and perhaps expand the original problem of... |
Because neutrons and protons consist of quarks, their magnetic moments differ from the so-called nuclear magneton (the natural unit for expressing magnetic dipole moments of nucleons).
A neutron has a finite magnetic dipole moment (possibly even an electric dipole moment) despite being electrically neutral: this is bec... |
The following is from Kleppner and Kolenkow's Introduction to Mechanics example 10.2:
Suppose that a comet with E > 0 (an extrasolar comet) drifts into the
solar system. From our discussion of the energy diagram for motion
under a gravitational force, the comet will approach the Sun and then
swing away, never to retur... |
Photons are known to be able to form 'molecules' through Rydberg Blockade, gaining some emergent mass, slowing down to subluminal speed.
But what is the force binding them together? Each photon doesn't have a charge so I assume they are not bound by electromagnetism. (Or are they?)
Or is it quantum entanglement that ke... |
How is ‘decimated’ data different from ‘undecimated’ data?
|
In Scaling and Renormalization in Statistical Physics there's following block of information:
I have some misunderstanding of some ideas.
1) How to define correlation length for arbitrary theory?
I understand, that asymptotically for free massive theory correlation length have form:
$$
\langle \phi(x) \phi(y) \rangle ... |
I am reading Wiseman et al. (2007) and Jones et al. (2007) papers on quantum steering. They relied on the existence of "optimal ensembles" for a Local Hidden State theory. They make use of group theory to find them from what I understood. I am confused as to how does group theory come in, in the first place. How do the... |
Suppose we have some model in statistical physics with Hamiltonian $H$ and partition function
$$Z=\mathrm{Tr}\left(e^{-H}\right) $$
the free energy per site is defined as
$$ f =\frac1N\log Z$$
A renormalization transformation is applied, and now the model has a new Hamiltonian $H'$. By definition the RG has to leave th... |
In Wikipedia there is this engineering definition of heat capacity
The heat capacity of an object, denoted by C, is the limit
$$ C=\lim_{\Delta T\rightarrow 0}\frac{\Delta Q}{\Delta T}$$
I'm very uncomfortable with this poor definition for a long time now. I want a rigorous definition purely based on statistical phys... |
I would like to read a book which rigorously defines what in applied thermodynamics is called "heat" and gives a proper derivation of the laws of thermodynamics from quantum statistics and the principle of Von Neumann entropy maximization.
I do not want a book which covers thermodynamics and then a bit of statistical p... |
Say we have a series circuit (containing a battery) with charges flowing through it.
We add a resistor to the circuit. The current should then decrease. If we add a 2 ohm resistor, the current would become lower than if we added a 1 ohm resistor.
Then say we add another resistor of 2 ohms. Based on what I have read, ... |
In the second equation of section 8.1 in this MIT OCW lecture notes, I can't understand how they went from
$$\rho_{S}(t)=Tr_{B}\{\rho_{SB}(t)\}=\sum_{k}\langle k|U_{SB}(\rho_{S}(0)\otimes|0\rangle\langle 0|_{B})U^{+}_{SB}|k\rangle$$ to
$$\rho_{S}(t)=\sum_{k}\langle k|U_{SB}|0\rangle \rho_{S}(0)\langle 0|U^{+}_{SB}|k\r... |
it is known (although I have not found much information about it on books and websites) that, while the divergence of $B$ is always zero ($\nabla\cdot B = 0$), we cannot say the same about $H$: the divergence of $H$ is zero only if the medium is homogeneous.
In fact (for instance suppose the medium to be isotropic and ... |
How does $\mathbf{F}=\mathbf{E}+i\mathbf{B}$ generalize to curved space? (where $\mathbf{F}$ is the bivector of electromagnetism).
Here is what I am struggling with:
On the one hand, I can expand $\mathbf{F}$ as follows:
$$
\mathbf{F}=E_x\gamma_0\wedge \gamma_1+E_y\gamma_0\wedge \gamma_2+E_z\gamma_0\wedge \gamma_3+B_x\... |
As far as I've understood, instantons like the sphaleron can give rise to processes that violate $B+L$ but conserve $B-L$, where the baryon and lepton number can only change by a multiple of three. That would imply the deuteron could decay in an antiproton and a few triplets of leptons.
I'm curious what the lifetime of... |
Everywhere I read something related to excited electrons in atoms I only see the word "lifetime".
For example most excited states have a lifetime of a few nano to micro seconds and metastable states have a lifetime of a few miliseconds as far as I understand.
Shouldn't we say "half-life" instead? Since we are dealing w... |
I am curious to know if a fan shaft will start to rotate due to a string being wrapped around it and the string is being pulled away by a tension spring which is attached to one of the fan blades.
The drawing below illustrates what this would look like.
The drawing is showing a front view of a fan with five blades. A ... |
As I know it, T-duality essentially tells us that if we compactify a superstring theory on a circle of radius $R$, it is equivalent to a string theory compactified on a circle of radius $\tfrac{\alpha'}{R}$. So, take $R\to\infty$. Then $R\to\infty$ and $\tfrac{\alpha'}{R}\to 0$. Hence, this should tell us that a string... |
In an automatic weather station, a temperature-measuring electronic sensor (which is typically 1,5 m in the air above a grassy ground and covered from direct sunlight) is in a certain way coupled to the computer inside the station and enables to show the temperature on a computer screen to one decimal place (such as 21... |
Imagine you have 2, 5 Litre bottles.
One of them is full of air at normal air pressure and is submerged at the bottom of a 5m tube full of water.
The submerged bottle has a piece of string hanging from the bottom of it, and it goes out of the bottom of the 5m tube (For arguements sake, lets say this is frictionless and... |
I was trying to write the sound horizon in terms of the scale factor, however I don't understand all the steps in the derivation.
I know that I should get:
$$r_{s}=\int_{0}^{a_{d}}\frac{da}{a^{2}H(a)}$$
What I tried
$$c_{s}dt=a(t) dr$$
Where $a(t)$ is the scale factor as the function of time, and $c_{s}$ is the velocit... |
I was watching this video (https://www.youtube.com/watch?v=KKQJIMdEEHY) to gain a better understanding about light polarization, but I was having some trouble with the derivation of the Jones Vector.
In the video, Professor Hafner made the assumption $k_{x}=k_{y}$ and $\omega_{x}=\omega_{y}$:
$\vec{E}=real \left\langle... |
I know that instantaneous power is defined as the time derivative of work done. For a constant, it is easy to prove that this is just the dot product of force and velocity.
However, is Instantaneous power even equal to to F.V for a variable force, and if so, how do I prove it.
I have tried to find this on the internet,... |
How can I calculate the temperature of a metal if at a distance of 1mm there is another heated metal that is at 3000K?
Note: the system works in vacuum
|
Now I study very interesting lectures Superconformal symmetry and representations and I face some statements, which are unclear to me.
In unitary CFT there are unitary bounds for dimensions of operators. When the unitarity bounds are saturated, there are null-vectors (i.e. vectors with zero
norm) in the representation.... |
An exercise of my Homework sheet make a statement about rotational variation on a scalar field $\phi(x)$:\
"Consider a scalar field $\phi(x,t)$ in a lagrangian $\mathcal{L}(\phi, \partial_t \phi, \nabla \phi$). Consider a spatial rotation such that $x^i \longrightarrow x'i = x^i + \omega ^i\ _j x^j = x^i + \delta x^i... |
Can we calculate heat liberated without changing our frame, in the situation of sand [from rest] falling on a moving conveyer belt maintained at steady speed.
And in question in picture, how is that heat is released as it is like an elastic collision between small particle entering tube and similar one leaving tube in... |
I know that the translational kinetic energy of ideal gas is $\dfrac{3}{2} nRT$.
What is the expression/formula for translational kinetic energy of a real gas ?
Does it change due to potential energy interaction in real gas which is not present in ideal gas?
Does it remain the same as $\dfrac{3}{2} nRT$ ?
Does it var... |
I am trying to derive the potential energy because of torque in a dipole placed in a uniform electric field. But the answer I am getting is different from the answer I saw everywhere. So could someone tell me, where in the integral or where have I made a mistake?
In the given diagram the total torque is given by $p\tim... |
I know what a Taylor series involves but you have to know the function; here $\mathcal{L}^*$ is just a function depending on $(v+w)^2$, any kind of function could be inside. How can the below approximation be done? and how this generalizes?
Does this have a name?
$$\mathcal{L}^*_0=\mathcal{L}_0((\vec{v}+\vec{w})^2)$$
... |
I was bored today and went on a random learning binge (I haven't touched this topic before today in a good decade since high school), and got stuck with this scenario I created for myself:
[I let myself assume c = 100m/s so the numbers would be "nicer" and make things easier to digest... I believe that doesn't invalid... |
I know that Fermi-Dirac statistics can be used to account for covalent bonding, but how does quantum mechanics explain hydrogen bonding?
|
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