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According to the Momentum Conservation Principle:
For a collision occurring between object 1 and object 2 in an isolated system, the total momentum of the two objects before the collision is equal to the total momentum of the two objects after the collision. That is, the momentum lost by object 1 is equal to the moment... |
I thought it should be $dU = TdS + \dfrac{1}{2}BdH +\dfrac{1}{2}HdB$, because the magnetic energy density is $$\dfrac{1}{2\mu}B^2=\dfrac{1}{2}HB$$
|
I know that the Tachyon state $c_1|0;k\rangle$, where $|0;k\rangle = e^{ikX}|0\rangle$, has eigenvalue $-1$ under $L_0$ operator. Using $L_0 = \alpha'p^2 + \sum_{n\ge1}\alpha_{-n}\cdot \alpha_n$ it is easy to see. Then if I define tachyon states as the zero level of the string states, the other $L_0$ eigenvector states... |
Recently a Nature paper Observation of branched flow of light shows observation of "branched flow" of a narrow laser beam hitting onto a well-controlled, stable bubble. The condition required is to have a suitable correlation length of the bubble:
(A very nice video regarding this: nature video: The laser show in a so... |
From my understanding the Seiberg-Witten map is a way to convert a non-commutative field theory into a commutative field theory. For example for the commutative relation between positions $[x, y]=i \theta$ the common SW map I see in the literature for non commutative quantum mechanics is
$$x\rightarrow x_{c}-\frac{1}{... |
I wasn't sure whether this question belongs here or on the maths page. Anyway I'm new here, and this may be a stupid question, so please forgive my ignorance.
Given that the force of gravity can be expressed as:
$$F = \dfrac{\mathrm{GM_1M_2} }{\mathrm{r^2}} $$
Assuming a two body system, is it possible to write this a... |
Chapter 3 of volume 1 of Weinberg's QFT says the following regarding in and out states in scattering theory:
Implicit in the definition of the states is a choice of the inertial frame from which the observer views the system; different observers see equivalent state-vectors, but not the same state-vector. In particula... |
In What is Life? published in 1944, physicist Erwin Schrodinger writes the following:
Why are atoms so small? To begin with, they are very small indeed.
Every little piece of matter handled in everyday life contains an
enormous number of them. Many examples have been devised to bring this
fact home to an audience, non... |
A system of phonons with continuous frequencies has a Hamiltonian like this $H=\int_0^{k_0} h(k) a_k^\dagger a_k \mathrm{d}k$. How do I calculate the partition function of this system using path integral?
Mathematically, how do I evaluate the following expression?
$$
Z(\beta)=\int\mathcal{D}? \exp{\int_0^\beta \mathrm{... |
Is Hamiltonian operator an operator that preserves the property of square integrability?
|
Galileo asserts that if a body accelerates uniformly, its velocity increases as the even integers ($1,2,3,4$ etc.) and therefore, the distances passed by the body in equal times increase as the odd integers $(1,3,5,7)$ etc.
This makes no sense to me. If we suppose that velocity is a continuous function of time, with $v... |
When we touch two metallic conductors one is neutral and other has excess of charges,
Case 1-
Both metals are of copper, then we can calculate actual charges on them at steady state by capacitance formula.
Case 2-
One metal is of copper and other of aluminium, and again we can calculate steady state charges by capacita... |
My home started seeing high water bills recently. My water company doesn't provide live water meter readings. There is a water meter on the street which I can monitor while water is being used but I would like to build a more comprehensive system which can present live water usage on some screen. The end goal is to sho... |
It's an example.
The satellite is moving around the earth. But when its height increases its velocity becomes low
|
While reading answers to the Were alchemist right?, I have come across the answer by @AndrewSteane. All in all he claims:
But the idea that it might be possible to transform one chemical
element into another is not at all a stupid idea. It is a perfectly
sound idea. However it turns out that it requires processes that... |
In Jackson's 9.14 we calculate the expressions for $E$ and $H$ of a loop antenna with current $I=I_0\cos(\omega t)$ in the $x-y$ plane in the radiation zone, where we approximate the distances to be large so:
$$\frac{1}{|\vec{r}-\vec{r}^{'}|}\approx\frac{1}{\vec{r}}$$
$$|\vec{r}-\vec{r}^{'}|\approx \vec{r}-\vec{r}.\vec... |
I was playing table tennis the other day when I my ball fell off the table. I placed my paddle above it in order to slow it down, and then I brought the paddle to the ground so that the ball would come to a stop. A diagram of what I did is below:
Why did the velocity of the ping pong ball increase so much at the end? ... |
For a particle that is confined in a volume $V$ the following relation is often used:
$\Delta^3 n = \frac V {(2 \pi \hbar)^3}\Delta^3P$
Since the particle is confined in $V$ it it doesn't have a determined momentum $P$, so it looks weird that there are $\Delta^3 n$ eigenstates of the momentum in $\Delta^3P$.
For this r... |
In some situations in mechanics, observing motion of bodies with respect to centre of mass often gives useful insights to visualize the situation and obtain many results.In some cases the motion of particles/rigid bodies with respect to centre of mass (COM) is circular. I would like to illustrate with the help of an ... |
An iron ore (natural magnet) in the earth's crust gets magnetized due to another magnet near it which aligns all its domains in one direction. We mine up that ore and use it to make other magnets (artificial magnets). The original magnet that had magnetized the ore had itself got magnetized due to another magnet. This ... |
I am wondering if there are any natural phenomenon in every-day life that cannot be explained by classical physics but can only be explained by quantum mechanics. By classical physics, I mean Newtonian mechanics and Maxwell's electromagnetic theory.
I know that there are macro-scale quantum phenomena such as supercondu... |
Is there any closed (even if complicated) formula por the Hawking evaporation time for a Kerr black hole (and more general black holes) just like the one
\begin{equation}
t_e=\dfrac{5120\pi G^2M_0^3}{\hbar c^4}
\end{equation}
for Schwarzschild black hole? Any reference about those? I am writing a black hole vademecum d... |
I wonder if we can convert dBm/MHz (eirp) to dBm?
For example:
What is the equivalent of -30 dBm/50MHz as dBm?
Edit 1: I wonder if power spectral density (dBm/MHz) can be expressed in dBm. In EN 302 065 ETSI standard, there are limits for power spectral density (see page 12) which are in dBm/MHz. I wonder if we can con... |
It's about the Goldhaber experiment, where the exercise I'm trying to solve is:
Photons are filtered according to their helicity thanks to the magnetic field. For a given
magnetic field, the electrons contained in the magnet see all spins flipped to a preferred
direction. When the magnetic field is inverted, all electr... |
I have always been confused by the idea of Earth being an approximately inertial frame as the speed at which it rotates is so high. Everywhere vaguely it is referred through calculation it can be seen that the frame is approximately inertial, what calculation would it be and is it compared to a theoretical model.
Thank... |
Let mass $m_1$ be placed at a distance of $x$ from the hinge such that the the plane makes an angle theta with horizontal
Then we drop $m_2$ at a particular distance $y$ from hinge such that after some time they remain at same height
Now potential energy of $m_2$ is
$$m_2(x+y)\sin\theta g - m_2(x)\sin\theta g$$
Simila... |
What are those bubbles/lines on the surface of my (clean) teacup after making tea with a tea bag (seethrough paper kind, wrapped in paper)? I used a kettle. The water is clean. Also what determines these patterns?
They have dissipated over 5 minutes or so.
|
Is there some reason behind the appearance of spin effects only under the application of variable magnetic field.
I know that we need variable magnetic field to act force on charge particle with some angular momentum, but I am comparing spin angular momentum with orbital angular momentum, i.e. we can detect orbital ang... |
I'm reading Friedman and Susskind's Special Relativity and Classical Field Theory.
They define the Lagrangian of a free particle
$$\mathcal L = -mc^2\sqrt{1-{v^2\over c^2}}$$
and then derive the corresponding Hamiltonian to be
$$H = \frac{mc^2}{\sqrt{1-{v^2\over c^2}}} .$$
Then they note that in the non-relativistic li... |
This online course on topology in condensed matter states the following:
We say that two gapped quantum systems are topologically equivalent if their Hamiltonians can be continuously deformed into each other without ever closing the energy gap.
This deformation of a Hamiltonian $H$ into $H'$ is given by
$$ H(\alpha) ... |
I'm trying to find out how to calculate the value of strong coupling constant. but haven't found any exact answer, all I get is reference to perturbation theory.
is there any exact defined formula to calculate strong coupling constant/ any data set related to it?
|
If we defined spacetime as a purely geometrical (not physical) structure of the kind that is in general relativity (a 4-dimensional Lorentzian manifold), would it automatically have properties that would behave like energy and momentum in Einstein field equations?
I am wondering whether the purely geometrical propertie... |
I can guess that it’s emission peaks at a higher temperature than white. So when a light is turned onto a black and white piece of paper, the initial condition is not at equilibrium. As black absorbs the light energy, it’s temp rises and then it re-emits photons at a lower frequency. Is there a quantitative description... |
A function $f(x,t)$ which satisfies the wave equation can be expressed generally as a function of a single argument $f(x-ct)$, where $c=\frac{\omega}{k}$. This is because you can express this function as an integral, according to Fourier Analysis:
$$f(x-ct)=\int^\infty_{-\infty}C(r)e^{ir(x-ct)}dr \tag{1}$$
The wave equ... |
Is there any general criteria for maximal entanglement in 3 qubit system. I have encountered this problem-"Suppose you have a state $\frac{1}{2}(|000\rangle + |110\rangle+ |011\rangle + |101\rangle)$. If the three qubits are labeled a, b, c, obtain the reduced density matrices $\rho_{ab}$ and
$\rho_a$. Argue why this... |
I saw in my course than when light hit a medium, it makes some dipole oscillating with the same frequency as the one of the light $\omega$. By a classical mechanics reasoning, one can show that the indice $n=\frac{\epsilon}{\epsilon_0}$ depends on the frequency,
$$n=n(\omega)$$
A wave is scattered by the medium, and th... |
This image is from here (page 6-7).
My question refers to Eq. 26 and 27
The denominator changed from $(p_1 -p_3)^2 - m^2$ to $p_3^2 - 2p_3p_1$.
So they used $p_1^2 = m^2$. But I thought, this relation is only valid for onshell particles. However, the propagator is offshell, and m is the mass of the propagator particle?... |
If we say that the $|\psi\rangle$ is in the Hilbert space what does the space of density matrix?
Is this phrase true?
$|\psi\rangle \langle\psi| \in V \otimes V_\mathrm{dual}$
$V$ is vector space.
|
I'm looking at Navier-Stokes equation in index notation and how to get them in vector notation:
$$
{\partial u_i \over \partial t}+ u_j {\partial u_i \over \partial x_j}= -\frac{1}{\rho}{\partial p \over \partial x_i}+ \nu {\partial^2 u_i \over \partial x_j \partial x_j}+g_i
$$
1st equation: The local acceleration, pr... |
In Peskin & Schroeder - Chapter 6 - the authors make the following approximation when $-q^2\rightarrow\infty$
$$\int_0^1 \!\!d\xi\, \frac{-q^2/2}{-q^2\xi(1-\xi)+m^2} \simeq \frac{1}{2}\int_0d\xi\, \frac{-q^2}{-q^2\xi+m^2} + \begin{pmatrix}\!\text{equal contribution}\!\\ \text{from } \xi\approx 1 \end{pmatrix}.\tag{6.64... |
Can I get some help interpreting the following?
"Since this is a total differential (that is, it only depends on the final state, not how the particle got there), we can integrate it and call the result kinetic energy."
This is from the derivation of the form of the kinetic energy from https://en.wikipedia.org/wiki/K... |
I'm studying stationary states and their orbital angular momentum in 3D Schrodinger equation. I have tried to understand by myself the situation but I get lost. I think it might be useful to know which cases are possible before starting the derivation by myself, so can you tell me:
Which of the following three situati... |
Most of the time, I read articles or watch videos saying that Hertz experiments validated Maxwell's theory of electromagnetism. But Hertz only confirmed the existence of waves (that are perhaps electromagnetic) and that they travel at the speed of light.
He did not for example confirm that these waves have both an elec... |
A spherical shell, uniformly charged, exerts no field inside it ; the point being either at centre or off-centre.
According to Gauss law if we construct a spherical Gaussian surface all inside the shell, it contains no charge inside and thereby zero net flux on that surface. Now, here we usually conclude that the field... |
Is it possible to construct some charge density $ρ(r)$ to get the Uehling-Potential?
$${\displaystyle V_{\text{Uehling}}(r)\approx -Z\alpha \hbar c{\frac {1}{r}}\left(1+{\frac {\alpha }{8\pi ^{2}{\sqrt {2}}}}\left({\frac {\lambda }{r}}\right)^{3/2}e^{-4\pi {\frac {r}{\lambda }}}\right)+{\mathcal {O}}(\alpha ^{3})}$$
Th... |
I was reading about the possibility that our universe could be a closed sphere.
from Sean Carroll “in a closed universe, one that wraps around on itself to form a compact geometry, like a three dimensional sphere ... cancels the positive energy from everything else. A closed universe has exactly zero energy”
There are ... |
Consider a circular loop of radius r and a wire of finite length which lies along the axis of the loop. Current I flows through the wire and.
I am trying to to find $\int \vec B \bullet d\vec l$ over the circular loop.
If I find magnetic field at a point on the loop And integrate it I get a non-zero answer but when I ... |
I've been looking for a term online but couldnt find it: suppose we have a subset $X$ in phase space, such that for all $q\in X$, the path starting at $q$ never exits $X$ either forward or backward in time.
Is there a name for such an $X$?
|
In example 10.6 titled "Satellite Orbit Transfer 1" of Kleppner and Kolenkow the author says
The most energy-efficient way to put a satellite into circular orbit
is to launch it into an elliptical transfer orbit whose apogee is at
the desired final radius. When the satellite is at apogee, it is
accelerated tangentiall... |
For the following problem, first problem in chapter 2 (page 16) of Landau and Lifshitz's Classical Mechanics text:
I am trying to see whether the picture I drew when originally solving the problem before looking at the solution
is valid. The answer would then be $\frac{\cos(\theta_1)}{\cos(\theta_2)}=$ ...
Based on t... |
I've been reading a lot about super-fluid vacuum/quantum foam/quantum vacuum etc and how quantum gravity (as hypothesized) will emerge out of interaction of these virtual particles that make up said vacuum. Further, they used some form of Navier-Stokes equation with time averaged viscosity taken as zero and to arrive a... |
A disk of radius r and mass M is oscillating inside a cylinder with a bigger radius R, without slipping. The goal is to find the dependency on $\omega$, the angular velocity of the disk, and $\frac{d\theta}{dt}$.
I've seen this problem solved using the relation of the length traveled by the center of mass $s=(R-r) \th... |
We learnt about the equilibrium a charged bubble would assume due to the suface tension and the electrostatic pressure.
$$\frac{4T}{R}=\frac{{\sigma}^2}{2{\epsilon}_o}$$
Where $T$ is the surface tension of the liquid, $R$ is the radius of the bubble and $\sigma$ is the surface charge density.
I was wondering if I cou... |
Suppose a simple setup where a free load (red) is supported by an inclined plane (pink) and a block at the end of the inclined plane (blue) touching the load as shown:
Is the force normal to the pink plane exerted by the red load smaller than that of the case where the load doesn't make contact with the blue block (as... |
Something that approaches infinity or is "essentially infinity" (an oxymoron) or is "near-zero" is the very opposite of the quality of infinity, and yet explanations tend to use these terms when explaining why black holes occupy an infinitely small volume. What about the creation of black holes makes them infinite on s... |
I am studying the application of the renormalization group to the $\varphi^4$ theory:
$$\mathcal{L} = -\frac{1}{2} \varphi (\Box + m^2)\varphi -\frac{\lambda}{4!}\varphi^4.$$
In particular I wanted to follow two different regularization methods, and verify that the resulting critical exponents $\nu$ did not differ, as ... |
I was solving a task dealing with electricity/magnetism, in which a charged, dimensionless particle was simultaneously affected by a uniform magnetic field and the electric field emitted by a fixed/stationary point charge, such that both of the resulting forces were centripetal and the particle was stated to be perform... |
I was skimming through the ITER Technical Basis and in page 16 of the PDF, under the subheading "Design Requirements", it says that the engineering requirements are:
I'm confused because these units do not match wikipedia's units for neutron flux and fluence:
Neutron flux: $\text{cm}^{-2}\text{s}^{-1}$
Neutron fluenc... |
I've been trying to solve this really hard problem (only for me maybe :) from Russian school olympiad for 1 week and I stucked. I tried to make some equivalent electric circuits, but I always end up on finding the capacitance of a parallel plate capacitor with different areas (how I understand there is no easy way to ... |
How does the magnetic field becomes 0 outside a toroid? Also how can we explain it with magnetic field lines?
|
I am finding the answer $\dfrac{-\mu_0 Q.m}{16\pi^2 \cdot r^5}\sin(\theta)$ direction to $\theta$ but the answer is $ r^4$. Where does the $r$ come from?
|
In his paper "Uniformly accelerated reference frames in Special Relativity", E. Desloge describes the acceleration of an accelerated observer through what he refers to as a direct application of the Lorentz transformation and the use of two inertial reference frames. The inertial reference frames Desloge references are... |
I believe this question may seem silly, every student who has studied quantum mechanics in school must has been told that Hamiltonian is a linear operator on Hilbert space.
However, today I think this statement doesn't make sense, because when we say something is a linear operator on vector space, we mean it acts on a ... |
I was trying to understand time dilation, but ended up getting more confused.
Why does it occur.
I saw the Wikipedia visualization here, which explained that a greater distance led to greater time (since 2nd postulate states that velocity is constant)
After seeing this, I had a list of questions:
1. What is so specia... |
Recently it's been theorized that "planet nine" may be a black hole.
If this is the case and we were to fly something out there, what unsolved problems in physics could be answered?
Additionally, if experiments were performed, what would they look like? Do we shine lasers at it? Drop entangled atoms into it?
I asked a ... |
The internet tells me that:
The voltage (from the power supply) is shared across each bulb in a series circuit because the energy carried by the electrons is used as they pass through the components.
However, I believe this is likely to be incorrect since electrons do not carry energy per se. At least I don't think t... |
I have read these threads
If black is the best absorber and radiator, why does it get hot?
Black and white matters. But why and how?
If a black body is a perfect absorber, why does it emit anything?
Why is black the best emitter?
Some respondents referred to the Stefan-Boltzmann Law and indeed were kind enough to do th... |
I have one probably very silly confusion about a footnote in the paper "2D Kac-Moody symmetry of 4D Yang-Mills theory
". In section (4) the authors consider ${\cal O}_k(E_k,z_k,\bar{z}_k)$ an operator which creates or annihilates a colored hard particle with energy $E_k\neq 0$ crossing the $S^2$ on ${\mathscr{I}}$ at t... |
If I'm laying in bed at night with the fan on, I cannot hear nearby traffic. If the fan is off, I can hear the traffic. What is/are the principle(s) involved in this phenomenon?
|
When comparing the weak gauge coupling to the electromagnetic gauge coupling (fine structure constant alpha) textbooks give the value ("relative strength") 10^-5 or the value 10^-13. Why are the values different?
|
I am self-studying SR and GR and need to make sense of the covariance principle. I understand the idea that physical principles should have no preference in coordinates and therefore must be expressed in a way such that it continues to be valid under a coordinate transformation from the 'covariance group'. In SR, the c... |
By definition, $G=F+PV$, where $G, F, P, V$ are Gibbs free energy, Helmholtz free energy, pressure and volume, respectively. How to derive the formula shown in the title ($g$ and $f$ are the density of Gibbs and Helmholtz free energy)?
I thought the energy density of the magnetic field is $\frac{1}{8\pi}H^2$ or $\frac{... |
Translation operator have the form
\begin{equation}
T_R = e^{i\frac{\hat{p}}{\hbar}\cdot R}
\end{equation}
and this can be easily proved, with $\hat{p}$ being the total momentum operator; but in mamy textbooks is stated that the generator for lattice translation is the Crystal momentum operator and that is not related ... |
I understand the directions indicated in the diagram below, but only in the case of main current ($I$) increasing. Say that ($I$) is a sine wave, and the time is between $\pi/2$ and $\pi$. This means ($I$) is still positive but is now decreasing, with magnetic field ($H$) doing the same. Wouldn't this cause the directi... |
Note: Closed for being off-topic (whoops!), see here for the re-post on the Engineering site.
If ships at sea can tack in a zigzaggy pattern by converting backwards force from the wind (using the sail) into sideways force, then that sideways force into forward force by bracing against the (stationary) via the rudder...... |
Infinite sums of increasingly higher-order derivatives, when present in Lagrangians, are typically taken as a sign of nonlocality. This is supposed to rule out fractional, negative and exotic (for example, $\exp(a\partial)$) derivatives from use in local field theories.
As far as I can tell, the intuition behind this i... |
I am trying to solve for the minimum of the hamiltonian of the form:
$$
H = \sum_{i,j} J_{ij}q(i)q(j) + g_i\sum_i x(i)
$$
where q(i) is the operator (I + z(i))/2 and z(i) and x(i) are pauli operators acting on the $i^{th}$ qubit.
What methods can I use to solve this? I know that this can be solved using a Variational Q... |
We know that moving charges produce magnetic fields if then all elements have electron with some non zero angular momentum so all substances must be magnetic to some extend.But this does not happen. But Only few substances are permanent magnet. I am confused why.
|
In the Stern-Gerlach experiment, they used a beam of silver atoms travelling in z direction (which has valence electron in the 5s shell), so the electrons carry zero angular momentum. Now since they have zero angular momentum, their magnetic moment must be zero. But when experiment was done by Stern and Gerlach, they e... |
Okay so I am VERY confused. Everything online is telling me that I can choose any reference point for potential being zero and still get a consistent result for potential difference HOWEVER I have only been able to see this when force is a constant (like with mg) and doesn’t depend on position then yes work done which ... |
When the high energy beam of particles or photon hits the cathode, electrons from $K$ shell are knocked in the generation of characteristic x-rays. Why do inner electrons get knocked out?
|
What would happen if we revisit the twin paradox in an empty universe? Indeed, according to Mach's principle, when a spaceship accelerates in our universe filled with too many stars and other objects, the observer in the cabin can claim that half of the universe is accelerated towards and the other half is accelerated ... |
As we all know, the probability current density in quantum mechanics is defined as: $$\textbf{J}=\dfrac{\hbar}{2mi}(\Psi^* \nabla \Psi-\Psi \nabla \Psi^*)$$ For simplicity let us work in one dimension and let us suppose a wave function $\Psi= A\ \text{cos}\ {kx}$. Applying the above definition and thus using $$J=\dfrac... |
Having some difficulties with the concept of pd in a circuit.
Potential difference is a measure of how much energy is used up between two points in a circuit.
However, see the picture I have drawn. In a circuit, there is a potential difference between the negative and positive terminals of the battery. This causes the ... |
My physics teacher told us that Torque is nothing but energy. I was very skeptical about this as torque is a vector qty. and energy is scalar, and over that torque is literally a force which makes bodies rotate how would it be energy?
|
I was solving a numerical example(image1) of 'Griffiths book of electrodynamics'
And in this solution it is given that if there is a changing magnetic field is there there would be induce induce electric field associated with it.
So now I take a example something like this (image2)
So as Griffiths example suggest t... |
The formula to describe the angle $\theta$ in a conical pendulum is:
$$
\theta = sin^{-1} \left( \frac{g}{l\omega^2}\right)
$$
This gives different results depending on if you use radians or degrees.
This is strange behaviour, how could you explain this?
|
I was learning the potential energy of a dipole because of torque from Halliday Resnick. In the given diagram, it said that if we move the system anticlockwise then the amount the Work that was done by the torque would be equal to $\displaystyle\int_{90}^θ-pE\sin θdθ$. Where Torque is given by $pΕ\sin θ$. Now potential... |
Suppose i have two very long parallel metal plates and i give them charges $Q_1$ and $Q_2 $respectively with $Q_1>Q_2$.The charges on the inner faces will be $(Q1-Q_2)/2 \ and \ -(Q_1-Q_2)/2$.If i connect these plates with a battery it is observed that the charges on the outer surface of the plates does not change and ... |
Suppose I have a fan blowing air. By Bernoulli's equation, the air pressure in the stream is lower than the air in the surrounding.
Here is my confusion: the moment I turn on the fan, the fan starts pumping extra air into the space in front of it and the air pressure there should actually be higher than in the surround... |
I want to apply a transformation to the rotating frame of a two level system such that a state in the transformed frame is $ |\hat{\phi} \rangle = U |\phi \rangle$, where U is the generator of rotations $ U = e^{i\omega J_{z}t}$ with its Hermitian conjugate $U^\dagger $.
Given the Hamiltonian in the stationary frame $H... |
I know that insulating materials are difficult to measure for insulating materials because there are charging. The effect is a drift or a moving micrograph.
Why does charging cause a drift in the image?
Is there some charge compensation at some point?
Is there a way to remedy to charging in insulating materials othe... |
The net rate of effusion of a gas through orifice is given by the following equation:
$$ r = \frac {\Delta P A}{\sqrt {2 π R T M}}$$
Rest being constant, the rate of effusion is inversely proportional to the square root of the absolute temperature.
But why is it so?
I mean as the absolute temperature increases so does ... |
I'm trying to understand friction but I'm getting a bit confused...
If I have a ring rotating on the ground around its COM what is the direction of the friction?
If I have the same ring, but this time it's on a rotating plate (the ring is not moving in the frame of the rotating plate but appears spinning at the same $\... |
For example, I can say the word "for" in two different tones. From a physics point of view, the waveforms of the sound signals will be different, but the ear will decode both of them as "for". SO I guess there are some components of both signals that are similar. What are those components?
|
I have a basic question in elementary quantum mechanics:
Consider the Hamiltonian $$H = -\frac{\hbar^2}{2m}\partial^2_x - V_0 \delta(x),$$ where $\delta(x)$ is the Dirac function. The eigen wave functions can have an odd or even parity under inversion. Amongst the even-parity wave functions, one represents a bound stat... |
There are two similar questions as the comment notified:
1. Reason for the discreteness arising in quantum mechanics?
2. How does quantization arise in quantum mechanics?
I could see two points there:
compactness of the space limited by potential.
symmetry requirement such as angular symmetry of atom, Lorentz symmetr... |
I am trying to solve Exercise 3.3 in TASI Lectures on AdS/CFT by João Penedones. It is solving for the scalar propagator $\Pi(X,Y)$ in AdS, and states as follows:
$$
\begin{align}
\frac{1}{2} J_{AB}J^{BA} \phi &= [X^2 \partial_X^2 + X \cdot \partial_X (d + X \cdot \partial_X)]\phi,
\tag{62}\label{62}
\\
\frac{1}{2} J_... |
I've been working on a simulation project of mine that I kind of need help with. So, as made obvious by the title, I am attempting to simulate the motion of a double spherical pendulum. I am writing my code in Java; Processing to be exact.
I was inspired by The Coding Train's video on this subject and it really caught ... |
Dark matter supposed to be affected only by gravity and no other force. At the same time, however, dark matter forms halos around galaxies, that become visible examining how galaxies and clusters bend the light.
The question is now, what does prevent these huge clouds of dark matter from collapsing? A cloud of "normal"... |
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