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This comes up in the context of a homework assignment. We're given the Euler equations for invisicid fluid flow. The variables at play:
$p=p(x,y,z,t)$ is pressure
$\rho = \rho(x,y,z,t)$ is mass density
$\vec v = \vec v(x,y,z,t)$ is velocity of the fluid
$\vec f$ is external force per volume
Then we're given that the ... |
I am trying to solve exercise 7 from chapter 2 of Goldstein, Poole, and Safko's Classical Mechanics, 3rd edition. I am getting the exact opposite of what it is asking and I don't know why. Can someone please help? The problem statement is: In example 2 of section 2.2, we considered the problem of the minimum surface... |
When reading about why SM neutrinos are not a candidate for DM, it was stated:
"Neutrinos are involved in weak interactions that keep them in thermal equilibrium in the early Universe down to the temperatures of few MeV."
A similar statement can be found here.
I don't understand how these interactions could maintain a ... |
I am recently studying thermodynamics and was wondering if energy is a state quantity, why aren't momentum and angular momentum? I feel like they are always zero at equilibrium in ideal gas based on Maxwell-Boltzman distribution. Is this general for all system in equilibrium? Thanks!
|
Why is it that we need ~99% pure silicon in order to have efficient solar cells? I understand that as silicon purity decreases so does solar cell efficiency but I'd like to understand why.
|
Reading Altland and Simons' "Condensed matter field theory" I am stuck in the exercise called "electron phonon coupling" in section 4.5.
The exercises is about integrating out the phonon fields to get an effective interaction between the fermionic fields. More precisely they write the action of such system as
$$
S[\bar... |
The Ising model on $\mathbb{Z}^2$ is given by the Hamiltonian $$ H(\sigma)=-\sum_{\{x,y\}}\sigma_x\sigma_y $$ and the Gibbs measure as $$ \frac{\exp(-\beta H(\sigma))}{Z_\beta}\,. $$
There exists an exact solution found by Onsager and re-derived later on by others. My question is:
On Wikipedia there are explicit expre... |
So ear candling is basically putting one end of the hollow candle in the ear and the other end is lit with fire. Now apparently this works because the burning creates a 'vacuum' which causes the earwax to move upwards. However, If this is correct then I don't understand why by burning upwards, the flow of the air goes ... |
Is this statement below true? I cannot visualise how the pivot can cause a 'Moment of Force' on the club and be responsible for changes in its angular momentum.
Consider a golf club fixed to a pivot - like a planar pendulum - about an axis through the grip end. Two forces act on the club: A contact force at the motionl... |
To preface my question, I'm coming to adiabatic quantum computing from a background in classical computer science with little knowledge of quantum physics, so simple, step-by-step explanations or references to helpful literature on this subject would be greatly appreciated.
A folk theorem of adiabatic quantum computati... |
I get it that we are transforming space and time in a different way, but how does that relate to changing the definitions of force and momentum? I thought that the Gallilean transformations were thought of as a separate thing from Newton's laws. Were Gallilean transformations an assumption of Newton's laws or something... |
I'm poking around Faraday's law regarding induction and I'm trying to solidify my understanding. In my figure below the light blue shaded area is a region of uniform magnetic field directed into the screen (signified by the one red X). If this magnetic field is increasing in magnitude at a constant rate, $dB/dt$, the... |
It has been made clear to me that 2 electrons in an orbital have opposite spins, and hence their spin magnetic moment nullify each other.
But does the same happen with the Orbital magnetic dipole moment as well or not?
Do the electron move around the Nucleus in opposite directions in one orbital?
|
Question. How do I explain to my dad what it means for some object to have a dimension of $1.5$?
My attempt. I tried to tell him the definition for an object to have a dimension $D$: if we scale up every dimension of the object by a factor of $S$, then the resultant object is comprised of $S^D$ copies of the original ... |
Consider an action integral $$I = \int_{t_0}^{t_f}L(\eta(\theta(t)),\dot{\eta}(\theta(t)),t)\,dt\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;(0)$$ with boundary conditions $\dot{\theta}(t_0) = \dot{\theta}(t_f)=0$ for some strictly-monotonic quantity $\theta(t)$ satisfying $\dot{\theta}(t) > 0$ in the open interval $t_0 < t < t_f$.
S... |
We have microwaves. Microwave ovens convert electricity into microwaves, specifically waves that resonate with water to make it hotter, thus heating my pizza in 3 minutes without disintegrating the plate it rests on until I devour it.
We basically shoot waves at something at a certain frequency, and it gets hotter. I r... |
Why is it necessary to burn the hydrogen fuel coming out of the engine for the lift of rockets?
If it is done to create a greater reaction force on the rocket then why can't we get the same lift with just adjusting the speed of the hydrogen gas going out of the engine like we can release them at a great pressure (and a... |
I saw several questions where I had to calculate the temperature of the air coming out of a tyre due to a burst, given the external atmospheric pressure and the initial state of the gas present in the tyre.
All these questions utilised the fact that as the air comes out rapidly, it can be assumed to be adiabatic.
All ... |
As per Energy Band Diagram of metals, the conduction band and valence bands overlap, But if we assume there is overlapping then the total number of energy bands will reduce as hence electron will have less number of energy states to occupy, which will violate Pauli exclusion principle.
For Example, suppose, if there ar... |
In our introductory solid state lectures, the professor described von Laue's$^1$ diffraction conditions making the assumption of elastic scattering, which states that the incoming and the scattered radiation have the same wavelength. We also assumed scattering by each lattice point in all directions.
Now, don't these s... |
One approach to squeeze light is through the one-mode squeezing operator, which can be written as $e^{-i H t}$ with $H \sim (a^2 - (a^\dagger)^2)$. My question is, can I create squeezing with $H \sim P^2 \sim (a-a^\dagger)^2$ ?
Is this described anywhere in the literature? I know it might not be easy to implement, and ... |
In my textbook under the subtopic
Similarities between biot-savart's law and Coulomb's law
It is written that the magnetic field is linear in its source Idl , just as the electric field is linear in its source , the electric charge
I'm unable to understand this point
|
Consider the block-pulley system in the image with bodies $m_1,m_2$ and $m_3$ having masses $1$ kg, $2$ kg and $3$ kg respectively. Assume the strings and pulleys are massless.
Will $m_2$ move downward or upward with respect to the ground?
The solution given is that it goes upward. But if $m_2$ and $m_3$ are considere... |
Please assume that there is no friction involved. In any wedge constraints problem,for example if two blocks are sliding over each other like this-
Sorry for the gap between both of them, they are actually in contact. Block B will slide down and block A will move in forward direction.
Now, I have often seen people ... |
We have antisymmetric wavefunctions for a fermionic systems and symmetric wavefunctions for bosonic systems that give us a hint that quantum states can be occupied by a single fermion(or none) while multiple bosons can occupy single quantum state(including zero bosons in a state). This shows how fermions behave in them... |
In quantum mechanics, if we have an operator $\Omega$, then under the transformation $T$, with infinitesimal generator $G$ (i.e. $T(\epsilon)=1-i\epsilon G + \ldots$), then operator transforms as
$$\Omega\rightarrow T^\dagger\Omega T,$$
so, infinitesimally,
$$\delta\Omega = T^\dagger\Omega T-\Omega$$
$$=(1+i\epsilon G)... |
This is found at the bottom of page 9 of David Tong's QFT lectures. The Euler-Lagrange equations for the complex scalar field:
$$\mathcal L=\frac{i}{2}(\psi^*\dot\psi-\dot{\psi^*}\psi)-\nabla\psi^*\cdot\nabla\psi-m\psi^*\psi \tag{1.15}.$$
However, to obtain the equation of motion for $\psi^*$, we need the following der... |
"For a person located inside a hermetically sealed box, there is no difference between being in space with the box accelerating and another person located in a similar box resting in a gravitational field."
What are the implications of Einstein's equivalence principle for physics? And why is it so important to us?
I ... |
I am not sure how a snail "sticks" to surfaces e.g. plastic pot or stone. I suspect that it produces mucus, which then adheres with molecular forces.
I would like to know, how does the contact surface between the snail and the surface maximizes the force with which the snail is attached to a surface.
|
$$dU=TdS-PdV+\mu d\bar{N}$$
$$\mu=\left(\frac{\partial U}{\partial \bar{N}}\right)_{S,V}$$
The energy of each photon is given by $\hbar\omega$ (each photon obviously carries energy). Therefore the addition of a photon to a photon gas must increase the internal energy. Why then is $\mu=0$?
Furthermore, many argue that $... |
I know that at the ends of a long solenoid induced magnetic field is $B= (μ_0NI)/2$. This is found by either integration or considering it as a part of a similar long solenoid.
But my question is that is there any way of calculating the same result by Ampere's circuital law? (Preferably without considering it as a par... |
At an equilibrium point of a system we consider that if we place the object (or in general the objects) there with zero Kinetic energy ,the object will stay there . The fact that the object stays there means that it will not change its position , thus the Potential energy will remain the same . Is this the intuitive in... |
I'm studying physics in the fifths semester and I'm still confused by some aspects of circular motion. So, I understand that the centripetal force changes the direction of the velocity, whereas the speed stays the same. But when the direction of the velocity changes, what causes the change of the tangential velocity at... |
I know that a body is rotating around its body axis (let us define it as $y_{body}$ with the angular velocity of $\vec{\omega}(t)=0.05 rad/s $. The rotation axis ($y_{body}$) is the interial y-axis which is rotated about 30° around the global x-axis and could be represented for example by the vector $$\begin{pmatrix}0 ... |
A rotating frame rotating at constant angular velocity with reference to a stationary one is considered non-inertial. This makes sense if one considers that the velocity vector of any point in the rotating frame is changing direction with respect to the stationary one, and is hence accelerating.
However, if one conside... |
Recently there was a result on triviality (or Gaussianity) of the Ising model and $\phi^4$-theory in dimension $d=4$. This therefore holds in any dimension $d \geq 4$.
We also know that the 2D Ising model is not trivial.
However, at the same time the 2D Ising model can be mapped to the (transverse field) 1D Quantum Isi... |
I don't understand the calculation of forces acting on a system vs the forces acting on an individual object in that system.
For example, here are two trolleys (1 and 2), joined with an inextensible rigid towbar in red
If trolley 1 starts exerting a force so that the whole system accelerates forwards...
The trolley e... |
Some time ago after discussing with my cooking friends I came up to a question:
Q: What makes water boil faster, adding salt a the begging or at the end of boiling?
A: Briefly, adding salt before makes water boil slightly faster (Salt and boiling speed )
That lead me to another question: the equality of energy consumpt... |
I asked a similar question here more than two years ago. I did not get an answer to my complete satisfaction. I would like to reiterate the problem again.
The local electric field of a monochromatic radiation is nonzero and varies sinusoidally in a predictable fashion. For example, the electric field of an ideal monoch... |
I was studying this chapter lately, and this part of chapter always confuse me. I often think why $3d$ orbital in transition metal is higher in energy than 4s orbital? (the whole question will refer to transition elements). My confusion arises when I look at the explanation on a website (attached below), it says that b... |
According to the Novikov's self consistency principle (also proposed by other authors such as Kip S Thorne) 1 2, if an event exists that would cause a paradox or any "change" to the past, then the probability of that event is zero.
But is the probability of that history exactly zero, or very close to zero? (i.e extreme... |
The formula for magnetic field density is B^2/2mu. How to prove it?
|
According to Poisson's book A relativist's toolkit, pag 52, with the Schwarzschild metric I can define outgoing radial null geodesic as follows:
$$u=t-\int f(r)^{-1} dr$$
where $f(r)=1-\dfrac{2m}{r}$.
Can I define an analogous geodetic in the Kerr spacetime, with
$$u=t-\int g(r,\theta) dr$$
where $g(r,\theta)=\dfrac{\S... |
Background
As per convention, Carroll defines the Levi-Civita symbol $\tilde{\epsilon}_{\mu_1 \mu_2 \dots \mu_n}$ as the sign of the permutation of $01\dots(n-1)$ on page 82. He states the Levi-Civita symbol has these components in any right-handed coordinate system (not necessarily orthogonal): they're defined not to ... |
When we move a magnet towards a coil, current is induced in it. Magnetic field too develops around it. Since there is interaction of both magnetic fields(that of magnet and coil), there is magnetic potential energy in field(gained from the work we do). This energy is going to do work on magnet (either in repulsion or a... |
In order to calculate work done against force of gravity we consider we have to apply a force of $F=mg$ on a object and we have to do work $W=mgh$. If gravitational force is also $mg$ how can an object be displaced against gravity with same amount of force? Both forces are equal and they are opposite in direction.
|
I'm trying to derive the expression of the time evolution operator, $\hat U$, in terms of the Hamiltonian of a system, $\hat H$. This operator $\hat U$ is defined so that $\Psi(x,t)=\hat U(t)\Psi(x,0)$.
My attempt at a solution
I have substituted $\Psi(x,t)$ by $\hat U(t)\Psi(x,0)$ in the time-dependent Schrödinger eq... |
According to A relativist's toolkit by Poisson, the expansion of null radial geodetic in the Schwarzschild spacetime is $$\theta=\dfrac{2}{r}$$
How to derive this expression?
The expansion is defined as $$\theta=k^\alpha_{\phantom{\alpha};\alpha} = \dfrac{1}{\sqrt{-g}} \left( \sqrt{-g}k^\alpha \right)_{,\alpha}$$
and $... |
Linear momentum of a system of particles is given by
$\vec p_{\rm net}=\vec p_1+\vec p_2+\vec p_3+ \ldots + \vec p_n$
Where $\vec p_{\rm net}$ is total linear momentum of the system and expression on RHS is vector sum of the individual particles' linear momenta
We can also write linear momentum of system of particles ... |
I am given a basis $|+\rangle = \frac{1}{\sqrt 2}(|0\rangle + |1\rangle)$ and $|-\rangle = \frac{1}{\sqrt 2}(|0\rangle - |1\rangle)$ and i am given a three qubit state $|\phi\rangle = \frac{1}{\sqrt 3}|1\rangle |0\rangle |1\rangle + \frac{2}{\sqrt 3}|0\rangle |1\rangle |0\rangle $
What is the probability of measuring s... |
I'm aware that 2-body problem has an analytical solution. However I was wondering what if we guessed for an answer and then checked whether it is a valid one. I know the equations and expressions governing the 2-body problem are the following:
\begin{align}
E &= \frac{1}{2} m_* \dot{r}^2 + \frac{1}{2} \frac{l^2}{m_* r^... |
It is straight-forward to verify that any Hermitian BdG Hamiltonian of the form
$$
\mathcal{H} = (c_1^\dagger, c_1, c_2^\dagger, c_2,...)
\begin{pmatrix}
H_{11} & H_{12} & \cdots \\
H_{21} & H_{22} & \cdots \\
\vdots & \vdots & \ddots
\end{pmatrix}
\begin{pmatrix}
c_1 \\ c_1^\dagger\\ c_2 \\ c_2^\dagger \\ \vdots
\en... |
For instance, im wondering if there were a glass I could expose an image using an enlarger, and fix the glass without using heat.
I doubt it, just curious to know if UV exposed, heat-cured photosensitive glasses are the only type.
Sorry if this is the wrong place to post. Let me know if there is a better place. (tried ... |
The time-evolution operator $\hat U$ is defined so that $\Psi(x,t)=\hat U(t)\Psi(x,0)$. In terms of the Hamiltonian, it is expressed as $\hat{U}(t)=\exp \left(-\frac{i t}{\hbar} \hat{H}\right)$. I'm trying to calculate the adjoint conjugate $\hat U^\dagger(t)$.
My attempt at a solution
It must satisfy $\langle \hat{U}... |
This question could apply to stars orbiting a black hole, or planets orbiting a star, or moons orbiting a planet. The example numbers don't matter, just the concept.
Lets say that a star has a gravitational time dilation factor of 2 of the level of an observer on Earth (i.e. time runs twice as slow as an observer on e... |
In the $^{235}U$, the binding energy per nucleon is around $7.6\ MeV$.
Once it has followed a fission, it splits in two objects, where each one has a typical binding energy per nucleon of around $8.4\ MeV$.
The resulting energy released is stated to be around 0.8 or 0.9 MeV per nucleon : $8.4 - 7.6\ MeV$.
My question i... |
I realize simulation is probably the way to go on this but I wanted to get an understanding of it. I'm going to put some electronics in a plastic box and it has to sit outside in the full sun. The electronics are directly attached with thermal paste to an aluminum heat-sink on the outside of the box. The box is 100mm x... |
I was learning about the double slit experiment and simple explanation is that there is wave interference. Although I do not quite understand the wave bit. We know that light is a wave.
But in the image of the wave interference we see something like two ripples (in water) that interfere.
I couldn't understand that ho... |
I see everywhere in the analysis of a spring-mass system of Simple Harmonic Motion, that each infinitesimal element on the spring of length $L$ is $\frac{vx}{L}$ where $v$ is the velocity of the block of mass on the end of the spring. It indeed makes intuitive sense that the closer the part of the spring is to the mass... |
Why does a drone fly with respect to the air in a moving car/airplane, but not in an elevator as shown in this clip: What Happens If You Fly a Drone In An Elevator?
I understand that the drone will move at the same speed as a moving car/airplane. Therefore, you'd have no trouble controlling it. However, according to th... |
In the beginning quantum mechanics is introduced by representing the states as cute little complex vectors, for example:
$$|a\rangle=a_+|a_+\rangle+a_-|a_-\rangle$$
this is a complex vector representing a state that can collapse in two possible states, with corrisponding probabilities $|a_+|^2,|a_-|^2$. On the other ha... |
I am just starting to solve the first couple of didactic problems of quantum mechanics, particles subjected to really simple Hamiltonians. Before checking them out I was thinking that the best approach to solve them would be to find the wave function using the Schrodinger's equation. Instead the first step seems to be ... |
According to Wikipedia, the energy released in a TNT explosion is 4 × 106 J/kg.
https://en.wikipedia.org/wiki/TNT
According to web, combusion of coal is around 24 × 106 J/kg.
https://www.world-nuclear.org/information-library/facts-and-figures/heat-values-of-various-fuels.aspx
This looks rather counter-intuitive: TNT is... |
The path integral evaluates ground state correlation functions, and when a symmetry is spontaneously broken, there are many ground states.
Defining the path integral of a QFT in the naive way, I don't see any room for there being a degeneracy of the ground state.
How does one determine that a symmetry is spontaneously ... |
I'm having a hard time understanding the permittivity of free space in my own words. Wikipedia defines the permittivity of free space as "the value of the absolute dielectric permittivity of classical vacuum." and it defines the absolute dielectric permittivity as "a measure of the electric polarizability of a dielectr... |
In Edmund Bertschinger's lecture notes Introduction to Tensor Calculus for General Relativity, following equation (14) he tells us:
The component $P_\mu$ of the one-form $\overset{\sim}{P}$ is often called the covariant component to distinguish it from the contravariant component $P^\mu$ of the vector $\vec{P}$ . In f... |
I’ve been trying to understand the relationship between conserved charges and symmetry transformations; in particular how the conserved charges act as generators for the symmetry in the Hamiltonian formalism and how, given a conserved charge, we can derive the associated symmetry. I’ve seen this referred to as the inv... |
I am having a hard time understanding the transformation of acceleration when it is not parallel to the instantaneous displacement of the particle, in particular the its dimension.
Suppose a particle is in projectile motion. Acceleration is downward because of gravity but I understand "uniform acceleration" depends on ... |
Outside an infinite length wire of radius a with even current distribution, the magnetic field vector for such a field would be
\begin{cases}
\frac{\mu_0Ir}{2\pi a^2} \hat{\theta} & r\leq a \\
\frac{\mu_0I}{2\pi r} \hat{\theta} & r\gt a
\end{cases}
Mathematically, this would mean that the curl would b... |
If a ball is on a hill with height $h$ defined by $h(x)$, then I'd like to find the equations of motion. The ball is in a uniform gravitational field. This is supposed to be compared to the situation in which $h(x) = U(x)$, and I am to evaluate under what limit the two scenarios become identical.
I actually began by tr... |
I have a projectile in 2D space $r=(x, y)$ at time $t_0=0$, which has an initial velocity $v_0$, a launch angle $\theta$ from $(1, 0)$ and which accelerates with a constant $a_0$ until time $t_1$ in the current flight direction of the projectile as well as a constant $g$ downwards $(0, -1)$.
This is, for example, a sim... |
I am following Topological Insulators and Topological Superconductors by B. A. Bernevig and T. L. Hughes. In ch. 16, the lattice model of 1D p-wave superconductor is solved by decomposing the complex fermion operators into Majorana fermions, as follow
\begin{equation}
c_{j} = \frac{1}{2}\left( \gamma_{2j-1}+ i \gamma_{... |
In classical electrodynamics books, I always see the radiation as perpendicular to the acceleration of an electric charge. For example in cyclotron radiation, and in antenna radiation.
However, intuitively based on looking at feynman diagrams, I would expect that photons should be emitted and absorbed at a 180' orient... |
Suppose, in frame $A$, two particles are present at $t=0$, at locations $x=1$, and $x=2$. Let's call these 'existence states of particles' to be events 1 and 2 respectively. We say that a force exists between the two events causing exchange of momentum between them.
In Galilean relativity, if we look at the same events... |
Will a parachute that holds 10kg have a greater terminal velocity than a parachute that holds 5kg? I've heard conflicting information so i'm not sure if it does. If it does then why and how does it increase the terminal velocity?
|
I am trying to simulate this coaxial transmission line setup for EMI shielding. Placed the Aluminium sample as seen below (in the middle).
I am new on this software, learned simulating the coaxial cable, but after adding the sample its showing peculiar results.
The em field lines are getting blocked at the sample. (see... |
I am reading an article, in which the phrase "crystalline long-range order" appears. I am not really sure what this phrase means here. I tried to find references online, but there seems to be little discussion of it. Does it refer to that, for example, the crystal has some periodicity along some direction in real space... |
I live (against my will) on the bottom floor of an apartment building, with a car road nearby. I made this text illustration to help you see the situation:
/ / /
/ /====+
/ / / =====+
/ / <-- Road ============================== <-- Walking road.
/ / / Ex-bush -> || v-- My window
... |
I have studied that friction is due to breaking of molecular bonds between surfaces while they are in motion. In the case below, I feel that since there isn't any motion, there will be no frictional force. But when I asked my physics teacher he said that there would be a frictional force, but I don't see why.
The yell... |
What is relative angular velocity of A wrt B and that of A wrt C in the figure given below?
Description:
A, B and C lie on a solid cylinder(rigid body) rotating with a constant angular velocity $\vec{\omega}$ about z axis
A and C lie on the plane perpendicular to $\vec{\omega}$
B lies directly below A with the same di... |
How to calculate $S$-matrix elements of quantum electrodynamics using path integral formalism?
|
My book told me a thing to keep in mind while doing upthrust sums in $\rm kgf$. It's stated as follows: (See point number 2)
Can you please explain why not to multiply with $g$?
Also I am giving another sum from my book, which I also couldn't do when I multiplied with g. The sum is:(See Sum No 1)
I have tried to make... |
Which of the following is a correct consequence of speed of light in a vacuum being the same for all observers?
A) The frame of reference of the observer is always the real frame of reference
B) Observations of events in distant galaxies are observations of events that occurred in the past
c) A clock that is moving rel... |
The heat q we provide is change in enthalpy. Also we measure entropy by the heat we provide with respect to Temperature(S=Q/T).
In gibbs equation,
dG= dH-TdS
dH is the energy we supply. Also TdS is also the energy we provide.
This makes me think that dG=0. But why it is not?
|
If a guitar pickup uses electromagnetic induction to induce AC current into a wire, does the low fundamental frequencies in that current carry more energy than the higher frequencies?
This is not a homework question, I am solving only life problems :)
|
By considering $\langle T^\alpha_\alpha\rangle$, the Weyl anomaly, we can show that the critical dimension, $D=26$ is the only possible choice of dimension for the bosonic string.
However, how do we know we can stop there? How do we know there doesn't exist a similar anomaly, that perhaps gives us a different critical ... |
I'm reading Sears/Zemansky book on physics, here:
The referenced figure is:
$\quad\quad\quad\quad\quad\quad\quad\quad$
I'm a bit confused, the center of gravity is given by $\tau = r_{cm} \times Mg$ and the torque is given by $\tau =r\times F$ where $r$ is a vector from the origin to where the force acts while $F$... |
Let us consider the vacuum energy of a scalar field in $d+1$-dimensional spacetime. We have the integral
$$I=\int\frac{d^d k}{(2\pi)^d}\frac{E_k}{2},$$
where $E_k=\sqrt{k^2+m^2}$ and $k$ is a $d$-dimensional vector. Now this integral is apparently divergent. We will employ the dimensional regularzation. We have a usefu... |
Does a uniformly charged ring, rotating about its axis produce Electric Field on its axis( as a non-rotating charged ring does)?
I am comfortable with elementary ideas that would come along with any given explanation.
|
Around 1906-1914 several classical experiments on scattering of $\alpha$-particles on gold and platinum foils have been performed by Rutherford, Geiger, and Marsden. In standard literature on the subject it is tacitly assumed that the atoms of gold and platinum remained at rest after the interaction with $\alpha$-part... |
As gravitons are formulated in current theories, are bodies supposed to radiate energy as they emit gravitons?
I thought that if bodies radiate energy, for big bodies this would be difficult to measure, as they emit a lot more energy in the form of heath, and smaller bodies in their orbits would get the energy back by ... |
In my book, I read that we can choose any level as Zero Gravitational P.E. and measure height of objects above it and call its energy 'mgh'. But by saying that all the points on that level is of zero potential, it can be inferred that it is an Equipotential surface but we know that all the points have different potenti... |
I was reading Kitaev 2009 periodic table paper when I came across the following
"Let us define the trivial hamiltonian:"
$$
\hat{H}_{\text {triv }}=\sum_{j}\left(\hat{a}_{j}^{\dagger} \hat{a}_{j}-\frac{1}{2}\right)=\hat{H}_{Q}
$$
where
$$
Q=\left(\begin{array}{ccccc}
0 & 1 & & & \\
-1 & 0 & & & \\
& & 0 & 1 & \\
& & -1... |
Lets imagine we have a spring of a linear characteristic such that the force the spring exerts is proportional to its deformation $\delta$. The spring is attached horizontally to a wall, now if we stretch the spring by applying a horizontal force $\vec{F}$ the work done on the spring will be:
$$W_{1\rightarrow 2}=\frac... |
Why are voltage and volt both are denoted by $V$? Won't it cause confusion?
|
My question is pretty simple, but I'll have to describe the problem in order to ask it:
We have a an RC circuit as we can see in the picture.
The given details are:
the resistance of the resistor $ R $, and $ C_1,C_2 $ are parallel plates capacitors, such that the area of the capacitor's $ C_1 $ plates is $ A $, and t... |
Suppose I have a Wigner function that falls off faster than any polynomial for all directions in phase space. That is, for all $a,b>0$, $$\lim_{|x|\to\infty} |x^a p^b W(x,p)| =0=\lim_{|p|\to\infty} |x^a p^b W(x,p)|,$$ which, when combined with the boundedness of its magnitude, is known to be equivalent to $|W|_{(a,b),(... |
When reading about the masses of neutrinos in the HDM (Hot Dark Matter) model of the universe, I came across the following equation:
$$\tag{1} \sum_i m_{\nu_i} = 92 \Omega_\nu h^2 \text{eV}$$
My problem arises with the statement that follows: "where the sum runs over all neutrino species with $M_{\nu_i} \leq 1$ MeV."
T... |
Do superconductors really have zero resistance in reality? If yes, then by ohm's law, I = V/R. I = V/zero. I = Infinity?
|
This question is a continuation of my previous question Rutherford scattering experiment, part 1 , but can be considered independently.
Around 1906-1914 several classical experiments on scattering of $\alpha$-particles on gold and platinum foils have been performed by Rutherford, Geiger, and Marsden.
In standard textb... |
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