All Questions

I have been reading the Classical Field theory part from The Quantum field theory book of Lewis H Ryder. After defining classical field $\phi(x^\mu)$ he says something about adding variations on both ...

I had the following question in my Quantum Mechanics test. A particle of mass m is subjected to a potential V(x) = β|x|, where β is a positive constant. Using the uncertainty relations (principle) ...

I have learned that a component of a uniform circular motion is an example of SHM. And I have no question about it, I totally understand that. I also understand how we can derive formulas like $\vec{...

I was trying to understand the origin of flat bands for twisted bilayer graphene and had a basic misunderstanding. The starting Hamiltonian is $$H = \begin{bmatrix} -iv_0 \sigma_{\theta/2}\nabla &&...

Let's consider particle in some potential $V(x)$. Newton law: $$m \ddot x= -\partial _x V(x)$$ After Galilean transformation: $$ x^\prime = x -vt \;\;\;\;\;\;\;\;\;\; t^\prime = t $$ Form of equation ...

Pseudo force always acts in a non-inertial frame and it is always opposite to the direction of the body's acceleration. The backward push is of course inertia, but can we consider it in this manner (...

** You have to write the angular momentum equation i.e. Torque = (Moment of Inertia)x(Angular Acceleration) for an infinitesimally small 3D element (about any axis of your choice). Finally, you have ...

Let's assume that we have two coordinates $q_1$ and $q_2$, a Lagrangian function $\mathcal{L}(q,\dot{q},t):=\mathcal{L}(q_1, q_2, \dot{q_1}, \dot{q_2},t)$ and a constraint $f(q,t) = 0$. Then I ...

I have been studying total internal refraction in waveguides and fibers. And to my understanding the higher the refractive index contrast is, the better the confinement of the modes propagating inside ...

My notes state that the spectral decomposition formula is of the form: $$ \hat{A} = \hat{A}\hat{1} = \sum{\hat{A} } |A_i\rangle\langle A_i | = \sum{A_i } |A_i\rangle\langle A_i | $$ Now consider the ...

My teacher says that Energy is in the form of Electric field. I've also seen the mathematical prove. (The amount of work done in bringing a charge from infinity to that point in the Electric Field) ...

Can someone figure it out for me how this formula arrives Provide derivation courtesy HC VERMA vol 1

For a free particle of rest mass m moving at speed v, the total energy (E), momentum (p) and kinetic energy (T) can be written in the relativistically correct forms: $E=γmc^2$, $p=γmv$, $T≡E-mc^2=(γ-1)...

I am following the book Braginsky and Khalili. Consider a measurement scheme where we connect a object to be measured to another quantum system which is then measured by classical devices.(Example: ...

Why is a compass not significantly affected by nearby (less than a couple meters) powerful magnets (such as those located inside home appliances and electronics) given Earth's magnetic field is just ...

How can you explain the statement that "the only central forces that result in closed orbits for all bound particles are the inverse square law and Hooke's law."

If i have a null geodetic on a $g_{\mu \nu}$ metric, it's also null in a generic $\hat{g}=\exp{2\omega(x)}g_{\mu \nu}$ for any $\exp{2\omega(x)}\geq 0$? What's the relation between affine parameter?

I was doing a Physics question and the question was: How does a satellite reduce their orbital radius. The answer was by ejecting mass (thus decreasing the mass) but it didn't explain more. This is my ...

In what sense from the  Church–Turing–Deutsch follows that it is possible to simulate with one physical system all the other physical systems? I know that we can build logic circuits with a Toffoli ...

In Hobsons's General Relativity: An Introduction for Physicists, pg. 64, he gave two different expressions for the affine connection $\Gamma'^a_{bc}$ in a transformed coordinate basis $x'^a$ (the ...

If a linearly polarized classical monochromatic electromagnetic radiation undergoes a scattering, does the scattered electric field have the same polarization as the incident electric field? I am ...

I got a Doubt that what if the spring has mass I found the following question When one end of a spring (of mass m and length l ) is pulled with velocity V1 and other and with velocity V2 then velocity ...

Could you, please, spot my mistake? Thank you in advance.

I could not understand why we can't use Gauss's Law to find the Electric Field of a finite charged sheet?

I have kind of been thinking about it for a while now and this is what i came up with. in the beginning there was nothing but space, no matter, space has a charge though and it repels itself because ...

So , everywhere I have looked for pair production it is stated that it cannnot happen in vacuum . Most proofs I have seen for that , state that the conservation of energy and momentum cannot be true ...

Typically a traveling photon is described as being in a superposition of frequency modes $\hat{E} = \int g(\omega) a^\dagger_\omega d\omega + h.c. $ where often the $g(\omega)$ is some kind of pulse. ...

Current, we say the earth on average is about 93,312,000 miles from the sun. And the sun has a diameter of 864,000 miles. Together they form a ratio of 108. Currently, we say the earth on average is ...

Consider two charge particles say Q1 and Q2 both are positive so they creates a electric field around it and both influence each other. Is it possible that both particles (or charge) creates a ...

Without involving Euler-Lagrangian equations. I wanted to prove the Lagrangian equation of the first kind. Basically, D'Alembert's principle says $$\sum_{i=1}^n (F^{a_i} - ma_{x_i})\cdot dx = 0,$$ ...

My Thermodynamics assignment is on this topic. Where do I start? My book does not cover the topic. Any reading material or any point to start with will be of great help!

Gas pressure needs a container for pressure. Yet science tells us that the atmosphere is the container. This impossible

At 9:07 in the latest Veritasium video, we see a map showing elevated levels of iodine-131 in the United States. The big band through the mid-west makes perfect sense to me; nuclear weapons tests ...

A follow-up question of the subspaces of 4-electrons: assume the magnetization of the system is conserved (the number of total spin-up $(\uparrow)$ particles is conserved), say 1, for example. Then ...

I have an spherical ballon filled with an ideal gas such that the difference of pressure between the interior $(P)$ and the exterior $(P_0)$ is proportional to the radius of the balloon: $$P-P_0 = \xi ...

It's most accepted that numbers and most related concepts do not exist in physical world, for example, since there're no 2 exactly identical leaves in this physical world, so there's no real copy of ...

I need to find the quadrupole expression from the dipole expression. I know that the dipole expression is $$V(\vec{r}) = \frac{1}{4\pi\epsilon_0}\frac{\vec{p}\cdot (\vec{r} - \vec{r}^\prime)}{|\vec{r} ...

I've come across a reaction shown as $ ^7\text{Li}(\alpha,\alpha^\prime)^7\text{Li}^*$. I understand that the asterisk indicates that the final $ ^7\text{Li}$ is in an excited state, but what about ...

Recently I made this video. It can be seen and heard that the remote control (MTLogic) of our TV doesn't work when I place an object between it and the TV. This is the remote control: It's obvious ...

Can anybody explain how to simplify the following system of capacitors given in the image below.

The gravitational force on a body due to another body is $\frac{Gmm'}{R^2}$ where the mass of the respective bodies are $m$ and $m'$ So the acceleration of one body (say mass $m$) be $\frac{F}{m}$ ...

Let's say that I held a hot object with a warm cloth. It instantly feels less hot and only warm to the touch. This is because the cloth is an insulator and doesn't allow as large a heat transfer as if ...

Let's say we have two point charges q1 and q2 both of which are positive, according to Newton's third law the force one exerts on the othe is equal to the force the other exerts on the first. ...

Meaning of pure rolling here: Rolling without slipping. Now moving to the question: In pure rolling there is only one type of force which is static friction which helps to start the pure rolling ...

Question: With its engine cut off, a small airplane glides downward at an angle of 15 degrees below the horizontal at a speed of 240 km/h b) If the airplane is initially at a height of 2000m above the ...

One of the things I am struggling with in working with electrostatics is in situations where a charge is surrounded by a concentric sphere, and Gauss's Law must be applied. Like if there is a metal ...

It stands to reason if gravity changes the color of light then the color will be affected by gravitational waves. My question is, when the waves pass, will the color change be permanent or will the ...

Many sources that say in free broadening of a Gaussian wavepacket, the momentum uncertainty (I think defined in terms of the range of 'significant' momentum amplitudes) is time invariant even as the ...

I have simulated a high penentration metasurface design and want to fabricate it. |E|^2 decays above the metasurface with very long ~ 1um decay length. What would be a good experimental way to measure ...

With the given details, An observer $O$ at rest relative to the garage with measured length $L_g$= 6.10 m. The garage is equipped with doors that can open or close instantaneously at a chosen time. ...