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While reading interference by the division of amplitude, I came across this doubt. Different sources seem to hint towards different answers. First, in wedge-shaped film, in the book Optics by Ajoy Ghatak, p210, considering an extended source, the formation of fringes on the wedge is schematically shown by the following... |
I was asked the following question:
Consider a car that weights $2$ tons and that stands on the ground so the area of each tire on the ground is $150\, cm^2$. How much pressure the car has on the ground?
I not familiar with this type of questions. Usually, I know how much the car weights and I use the Newton's laws t... |
We know that a photon can split into an electron-positron pair and that when an electron and positron come into contact they annihilate and produce a photon.
But why does this happen?
|
Properties of photons are quantised right? So what if we red shift the photons with the lowest possible frequency?
|
The "Introduction to Plasma Physics C17 Lecture Notes", which I'm reading online, set out the following scenario in section 1.1.2:
Consider the electric field due to a 1-D line of charge (see Fig.
1.2). Applying Gauss' theorem to the pillbox shown, we find $$ \int E.ds = 2AE = \rho A dx/\epsilon_0$$
Here is the diagr... |
Why is the octet rule true?
How can electrons even stay around nuclei with lesser number of protons?
|
Are following suggestions ok to cap the energy of a photon?
When the photons have enough energy in a small enough volume to collapse into a black hole
When the wavelength of the photons becomes the smallest possible. That is, some unit of space is indivisible and fundamental.
|
Even after increasing the frequency why does the the ratio of
Number of electron ejecting/number of capable photons to take out the electron remains constant?
Check the image attached.
|
ERROR: type should be string, got "https://glossary.periodni.com/glossary.php?page=41&en=high+fructose pictures like the ones in this article make no sense to me.\nI understand that we can take solutions to the Schrödinger equation and make normalised linear combinations to get new solutions. But how do we combine the spherically symmetric 2s solution with the 1px, 1py, 1pz solutions which are symmetric in the x, y and z planes respectively to form sp3 solutions that only show cylindrical symmetry?\nWikipedia says that the sp3 orbitals are 25% 2s orbitals and 75% p orbitals which makes sense but I don't see how that makes for such asymmetrical orbitals.\nI can't believe I'm having such difficulties finding information about this\n" |
What is the definition of simple harmonic motion? The motion of a particle where its displacement is given by a sinusoidal function, that is: $$x=A\sin(ωt+φ)$$ or the total force that is acting on the particle is: $$ΣF=-kx$$
Also why we need to show that for a particle undergoing simple harmonic motion the force is in ... |
I am confused on a trivial problem here involving Newton's 3rd Law and the FBD of the following problem,
where the question asks for the differential equation of motion, with $V_2$ as output and $V_1$ as input. It also asks for the implicit force associating $V_1$ and $V_2$.
The velocity $V_2$ here is relative to $V_... |
One step in finding the interface conditions for electromagnetic waves involves recognizing that as $\vec{A}\rightarrow 0$, $\int_{\vec{A}}\frac{d\vec{B}}{dt}d\vec{A}=0$. Specifically, we usually treat $A$ as a rectangle with one side begin driven to zero. This is justified as $\frac{d\vec{B}}{dt}$ is finite.
Of cours... |
When deriving the transition rates for atoms in radiation, one calculates the rate for a single frequency and then adds the rates corresponding to all frequencies in the spectrum. The reason for this comes down to the fact that the radiation is incoherent, so we add intensities instead of amplitudes.
I was under the im... |
I was going through the texts of my book and read that intensity of a wave is proportional to its amplitude squared. I don't know how this relation came?
I thought for it but didn't come with any solution. My intuition was this :
Amplitude of fields is proportional to the energy supplied to an oscillating charge becaus... |
It is known that you can calculate the distance to a planet using parallax, but how do scientists calculate the orbital period of a planet?
(Assuming they don't know the distance and can't use Kepler's law)
|
https://www.youtube.com/watch?v=-1s0K_MKAgI&t=303s
In this video at 3:55, Mr. Wangchuck explains that the ice stupa doesn't melt because it has less surface area for a given volume compared to other figures in geometry (being a cone). I have theorized it happens due to it having a lesser exposed surface area and hence,... |
I was learning about wind from my class textbook. In that there is first a description of forces affecting the velocity and direction of wind followed by that is geostrophic wind.
My question is:
At one instance it is written that Coriolis force acts perpendicular to the pressure gradient force and in the next paragrap... |
I have thought that the cancellation of peaks and troughs is a consequence of Newton's third law of motion that equal and opposite forces cancel each other out.
Or it has something to do with conservation of energy or momentum.But I have never truly understood it correctly.
I believe there is an obvious and clear expla... |
I find the treatment of time-dependent perturbation theory in Griffiths to be quite difficult/intensive. Our professor introduced us to the idea of using the interaction picture and this feels much easier to me so far. Are there any well-received undergraduate QM textbooks which take this approach? Problems/examples a ... |
While solving Schrödinger equation for Hydrogen atom we make a scale transformation for radial variable ($r=\frac{ax}{Z}$; where $a=$ Bohr radius, $x=$ dimensionless variable and $Z=$ atomic number), this turns out to be a very good scale transformation. But my question is how do we know value of Bohr radius in advance... |
Consider a fermion $N$ with mass $m_{N}$ and coupling to an active neutrino $\nu$ via the mixing
$$
\mathcal{L} = m_{N}\theta \bar{N}\nu,
$$
where $\theta\ll 1$ is the mixing angle.
It is known that in the hot plasma medium the mixing angle is suppressed:
$$
\tag 1 \theta_{M} = \frac{\theta}{1+f(T,m_{N})},
$$
with $f(T... |
The 3-dimensional free electron density of states (DOS) including spin degeneracy is:
$$g(E)=\frac{1}{2\pi^2}\left(\frac{2m_e}{\hbar^2}\right)^{3/2}\sqrt{E}$$ where $m_e$ is the electron mass, and $E$ is the energy.
(a) Write down the DOS, $g_c(E)$ and $g_v(E)$, for the conduction and valence band edges of a semicondu... |
I had incidentally noticed this. An ice cube that fell on the kitchen granite platform started to melt and as it melted it also started to rotate. I tried to stop it by touching it, but it starts to rotate again when I release it. I captured a video of it and it available here: https://www.youtube.com/watch?v=9B59iG_Be... |
Let's consider a point particle $A$ in motion with fixed distance from the origin. Its vector position $\mathbf{A}$ has this property:
$$
|\mathbf{A}|=\textrm{constant}
$$
By calculating $\frac{d|A|^2}{dt}=\frac{d|\mathbf{A} \cdot \mathbf{A}|}{dt}$ it is easy to see that
$$
\dot{\mathbf{A}} \cdot \mathbf{A} = 0
$$
but ... |
The question asks for heat produced in the given specific conditions. It seems like an application of the work-energy theorem with friction doing work on the block and dissipating the heat in the process. I decided to do it from two frames:- 1) the ground frame and 2) the belt frame and expected to get the same answer... |
This question defines a streamline as NASA do, i.e. by looking at air particles movement. But I'm confused by special cases:
if there is no wind, air particles are still moving, but we take the average movement on all point we get a field of null velocities.
given this answer, it seems that NASA call "air particles" a... |
Case 1
This is a very commonly discussed case in Electromagnetic Induction. In the case above, we need to find out the potential difference across the rod CD, in the presence of time-varying uniformly distributed cylindrical magnetic field as shown in the figure above.
Here we say that in equilibrium, the non-conserva... |
Polchinski uses the graviton-dilaton action (8.1.9) in his String Theory book
$$S_1= \frac{1}{2\kappa_0^2}\int d^D x\, \sqrt{-G} e^{-2\Phi} \left[ {R} + 4 \nabla_\mu\Phi \nabla^\mu \Phi \right] \tag{8.1.9} $$
for the Kaluza-Klein theory. He then rewrites this in terms of the Kaluza-Klein fields as
$$S_1= \frac{\pi R }... |
The above image is taken from the book concepts of Physics by Hc verma.
I am having a bit of trouble understanding that the direction of electric field will always be perpendicular to the curved part of the cylinder
Now consider the electric field made by this particle in the linear charge distribution all the partic... |
I am looking at the first three pages of this file (https://www.mtholyoke.edu/courses/tdray/phys310/electromag.pdf).
In the lab frame, there is an infinitely long wire stretching from left to right, consisting of positive and negative charges with equal linear charge density $\lambda_+ = \lambda_-$ so that the wire is ... |
In a static and spherically symmetric space-time, using the standard coordinates $\{t,r,\theta,\phi\}$
the geodesic equations imply that
$$
g_{rr}\biggl(\frac{dr}{d\tau}\biggr)^2+\frac{J^2}{r^2}-\frac{E^2}{g_{tt}}=-1
$$
where $J$ and $E$ are the conserved quantities and $\tau$ is the proper time along the curve. Dividi... |
Assume we define the locality of a theory in the following way:
Assume we have a theory of real scalars, so this theory is non local if the action has terms like
$$\int d^dx\,\phi(x)V(x-y)\phi(y).$$
If the action does not have such interaction terms that are a product of the fields at different positions, the action is... |
I know that the basic definition of the work done on a particle is: $$W_{12}=\int_1^2\mathbf{F}\cdot\mathrm{d}\mathbf{r}$$
but what if I have want to calculate the work done on a rigid body? is the formula the same?
|
$$1.(R_{B/A})_{/A} = (R_{B/A})_{/O}$$
$$2.(\frac{dR_{B/A}}{dt})_{/O} = (\frac{dR_{B/A}}{dt})_{/P} + w_{/O} \times (R_{B/A})_{/A}$$
If $1$ is right , then, $2$ becomes:
$$(\frac{dR_{B/A}}{dt})_{/O} = (\frac{dR_{B/A}}{dt})_{/P} + w_{/O} \times (R_{B/A})_{/A}$$
My question is:
Can I claim that a displacement vector doesn... |
We know that capacitance of a conductor is the ratio of charge stored in it to the potential at the surface of the conductor, $C=q/V$. But how is capacitance of a capacitor consisting of $2$ conductors defined ($\mathrm{C = q/(p.d)}$ between conductors). I want to see the derivation involved that led to this conclusion... |
We know that any field can be constructed using its divergence and rotational. The divergence of the magnetic field is always zero. However its rotational is proportional to the current density. According to Ampere law, locally, outside of the current filament, the rotational of the magnetic field is zero, but its dive... |
My textbook reads
“ Two equipotential surfaces can never intersect because if they did, at the point of intersection, the field would have to have two directions (perpendicular to each surface) which is clearly absurd..”
I understand the fact that if there were to be a non-zero field at each point of the surface then s... |
I am getting confused when it comes to motion of two movable bodies joined by the ends of a string wherein one of them is given some velocity (making a certain angle to the string joining the bodies). When do we have to conserve linear momentum and when are the components of velocities equal?
For example in this questi... |
In decoherence theory, the basic situation is the following (I illustrate with two level system for simplicity). I want to measure a system $S$ by the mean of an apparatus $A$. Around it there is the environment $E$. The initial state of the apparatus is $|0\rangle$, the initial state of the environment is $|E_0\rangle... |
Suppose I send linearly polarized light onto a hydrogen atom. Using first order perturbation theory one can show that, depending on the relative polarization of the light to the quantization axis of the hydrogen, either $$m=0 \quad\quad\textrm{or}\quad\quad m=\pm1$$ for the transitions, that can be excited. $m=0$ hold... |
I read literature about superconductor BSCCO ($Bi_2Sr_2CuO_{7-x}$) and came across a very interesting term.
It is said that the process of removing oxygen atoms, in which a pure substance becomes a superconductor, is called hole doping.
I do not quite understand this term in relation to this situation. Oxygen is remove... |
We have studied Two lens system, I wanted to know how to formulate when there are Multiple Lenses.
Like How the formula for Effective Focal length changes when there are $2$ or more lenses.
For example: Consider a $3$ thin lens system, the effective focal length would be $F=f_1+f_2+f_3-d_1f_1f_2-d_2f_2f_3$ ?
Where $d_1... |
I have been told by many lecturers and many books that in the Schwarzschild metric
$$
ds^2=-\left(1-\frac{r_s}{r}\right)dt^2 + \left(1-\frac{r_s}{r}\right)^{-1} dr^2 + r^2 d\Omega ^2
$$
the singularity at $r=r_s$ purely comes from the bad choice of coordinate and that there is no physical singularity there.
I got reall... |
Consider the diffusion equation,
$\frac{\partial n(x,t)}{\partial t}=D\frac{\partial ^2n(x,t)}{\partial x^2}$,
inside a box from $x=0$ to $x=L$ subject to the boundary conditions
$n(x=0)=0$,
$n(x=L)=1$.
One can show that
$n(x)=x/L$
is a steady-state solution that satisfies the boundary conditions. Since this is a stead... |
I put a pot of water in the oven at $\mathrm{500^\circ F}$ ($\mathrm{260^\circ C}$ , $\mathrm{533 K}$). Over time most of the water evaporated away but it never boiled. Why doesn't it boil?
|
Suppose I'm looking at a particle system in a $2D$ box, with $N$ particles with position $(x_i(t),y_i(t))\; i=1,..,N$. Lets assume I know the temperature at any point in the box at any time $T(x,y,t)$. The motion can be described by Newton's equations:
$$m_i \frac{d^2x_i}{dt^2} = - \frac{ \partial U_i}{ \partial x_i}\\... |
In decoherence theory, we explain the decoherence by hamiltonian evolutions between a system and its environment. Calling $H$ the total hamiltonian, I have:
$$H=H_S + H_E + H_{SE} $$
A pointer state $|s\rangle$ is a state of the system $S$ for which the associated observable $|s\rangle \langle s |$ will commute with th... |
We know the universe has end or loop. Popularly there are $3$ ways for it. So we can not stop it but can we maybe escape from it?
Edit: Ikr it looks IMPOSSIBLE. But isn't there ANYWAY?
|
I want to calculate the reflection efficiency of a transmitting monopole antenna which is connected to a 50 ohm lossless transmission line. And I know that the input impedance of a monopole antenna is 36.5+21.25i ohm.
I tried the following ways to calculate the reflection efficiency but ended up with different values a... |
So I can define the quark distribution function within a hadron as
$$
f_{\psi/h}(x)=\frac{1}{2}\int\frac{dz^-}{2\pi}e^{ixP^+z^-}
\langle h(p)|\bar{\psi}(0)\gamma^+\psi(z^-)|h(p)\rangle|_{z^2=0}
$$
where $a^{\pm}=\frac{1}{\sqrt{2}}(a^0 \pm a^3)$, and where $A^+=0$.
This can be constructed from the lower half of the hand... |
The units of 'parsecs per cubic centimeter' is really hurting my brain...
Could someone please explain this weird astronomical unit?
|
Say I have a quantum system with a symmetric potential, whose symmetry is described by a group $G$. I know the character table of $G$, its irreducible representations, can work out the projection operators $\Pi_j$ etc.
With imaginary time evolution, I can find the spatial part of the energy eigenstates $\phi_{E_i}$. If... |
A capacitor in parallel with a resistor will have a random noise $\mathrm{voltage^2}$ across it of average value $V^2 = k_{B}T/C$. If this is a parallel plate capacitor, you can show that the average attractive force between the plates is $k_{B}T/d$ where '$d$' is the spacing.
Note that this is not the same as the Casi... |
OK, so I know that charge flows from high potential to low potential, for eg. if there were $2$ spheres of $5V$ and $3V$, then charge would keep flowing until their potentials become equal, i.e. $4V$, so then even in the case of a sphere and wire, charge should flow from the sphere to wire until their potential becomes... |
Let’s say we have a horizontal spring system with a spring attached to a wall, and a mass attached to the spring. If I pull the mass back, stretching the spring out, and then let go, the mass will accelerate, and the spring will begin to compress. I understand that as common sense.
According to newton's third law, if ... |
I want to ask about angular motion. Suppose a circle of radius $r$ rotating with angular acceleration $\alpha$. I know that the polar coordinates of a point in the perimeter of the circle is $(r,\theta)$. Transforming this to cartesian, it becomes $(r\cos\theta, r\sin \theta)$.
I know that the angular position can be c... |
The ground electronic configuration of Carbon is $1s^2$$2s^2$$2p^2$
$l_1=1$ and $l_2=1$ $\implies$ $L=2,1,0$
$s_1 = \frac{1}{2}$ and $s_2=\frac{1}{2}$ $\implies S=1,0$
So the terms are $^{3}D,^{1}D,^{3}P,^{1}P,^{3}S,^{1}S$. However, only $^{1}D,^{3}P,^{1}S$ will survive because of Pauli exclusion principle.
My questio... |
There are many questions on this site that ask whether the expansion of space could instead be interpreted as a speed of light that changes over time, e.g.:
Has the speed of light changed over time?
Space expanding, or light slowing down?
$c$ slowing down rather than universe expanding?
Is the universe expanding at an ... |
So I read somewhere that if you place a charge inside a cube the induced charge is distributed non-uniformly;its more concentrated on the edges and corners. And its in not just this case; I have also read directions stating, 'Ignore edge effects' while solving problems. Why are edges so susceptible to a high charge den... |
If operator $\hat{A^{\dagger}}$ is the hermitian conjugate (adjoint) of $\hat{A}$, i.e.
$\left\langle \hat{A^{\dagger}}\psi \middle|\psi \right\rangle = \left\langle \psi \middle|\hat{A}\psi \right\rangle$, is $$\left\langle \left( \hat{A^{\dagger}} \right)^n\psi \middle|\psi \right\rangle = \left\langle \psi \middle| ... |
The picture of wiki showed some strings attached on D-branes. However, consider those D2 branes in 3 dimensional world. Then D2 branes had two "sides".
Case 1.
Let a string started at one of such D2 brain(A) on the up side(U) and ended at the down side(D). Would it be a different particle than that of a photon i.e. a s... |
Could anyone explain the equation for total energy and relativistic momentum, why do they have a Lorentz factor in them? I also understand that these equations are derived such that they keep the laws of physics the same in all inertial frames of reference, but how does it do that?
|
In Michelson's Interferometer (1881 experiment), even though the arm length for both the perpendicular arms was taken as the same (say $L$) and a compensatory plate was used to removed optical path differences, we still get a proper interference pattern despite both the rays reaching the observational lens in parallel... |
I can't seem to understand this question, I can get the electric force between the charges using distance a but don't understand what I should do after that.
The electric field is a vector and so two electric fields at the same point in space must be added according to the laws of vector addition. Consider two equal p... |
If the four-vector $x^\mu$ is defined as $x^\mu\equiv(ict,{\bf x})$, instead of $x^\mu\equiv (ct,{\bf x})$, the Lorentz group will be the compact(?) ${\rm SO}(4, \mathbb{C})$ group. But the Lorentz group is regarded as the noncompact group ${\rm SO}(3,1)$. But I could never figure out what is the real problem of using ... |
Is there any way to prevent or minimize reflections of water waves in something like a ripple tank? I'm thinking maybe something analogous to acoustic sound panels (I believe they use foam properties to absorb sound) could be helpful. Or alternatively, maybe something analogous to shock absorbers would be relevant.
|
I am reading Quantum Statistics from 'Fundamentals of Statistical and Thermal Physics' by Frederick Reif. I have questions in two places.
I understand the following paragraph:
Particles with half-integral spin (Fermi-Dirac statistics):
This is applicable when each particle has a total spin angular momentum (measured i... |
If we take a satellite rotating around the earth, then the earth applies centripetal force to the satellite, but what if the satellite suddenly looses kinetic energy, maybe because of collision, the point is that now it goes slower. The gravitational force is the same, but the velocity is less, so does that mean that t... |
I am learning differential geometry from Hobson et al, General Relativity: An Introduction for Physicists.
In pg. 36 of the book, the author tries to show that the line element on the surface of a sphere can be locally reduced to the Euclidean form $ds^2=dx^2+dy^2$.
He starts with the 3D cartesian coordinate system $(x... |
Suppose I have two spherical soap bubbles of volumes $V_1$ and $V_2$. Suppose, they are found to coalesce under isothermal conditions to form another bubble. Is the volume of this resulting bubble the direct addition of the volumes $V_1$ and $V_2$? Why, or why not? The total quantity(moles) of air must remain conserved... |
so I'm currently learning quantum mechanics in the context of a physical chemistry course. So it's not very mathematical which leads to a lot of little traps that just confuse me.
Let me first introduce the Bra-Ket Notation I'm going to use. The inner product of two complex valued functions $\varphi_m$ and $\varphi_n$ ... |
If there is any sort of field in a conductor, then the charge would rearrange such that the field is canceled. Then, why is it that there is electron flow in the circuit? Or is it that at each point the 'charge' density is same at all points?
|
In his GR book, Carroll states following in the chapter- 6 (More general black holes)
Usually, we like to associate the entropy of a system with the logarithm of the number of accessible quantum states. There is, therefore, some tension between this concept and the no-hair theorem, which indicates that there are very ... |
In the case of a perturbed Hamiltonian $H_0$
\begin{equation}
H=H_0 +\theta(t-t_0)W(t)
\end{equation}
at $t=t_0$ the Hamiltonian admits eigenvalues $E_n(t_0)$ and for positive $t-t_0$ then the eigenvalues are $E_n(t)$. The Kubo formula then states that, up to linear order in $W(t)$, the expectation value of an operato... |
Consider the following two scenarios:
a) A particle is rotating in the $x-y$ plane about some point fixed in lab frame at a radius $a$ with relativistic angular speed $\omega$. Do not include the stress-energy of whatever forces keep them in orbit.
b) A particle is rotating in the $x-y$ plane about some point fixed in ... |
Why is an image formed where the direction of incident ray meets?For example:If a light ray is incident on a plane mirror , the ray will partly reflect and refract.Now the position where the direction of incident ray meets and a ray perpendicular to the plane mirror is where the image is formed.Why is it like that?Sinc... |
So, I'm given a certain wavelength $\lambda$ and the grating costant $d$ (distance between slits). I'm asked to find the maximum order of diffraction for this set of data. In general, when light falls upon the grating with angle $\theta_i$ and escapes (I don't know the right word in English, sorry) with an angle $\thet... |
Question:
How do we write the unitary evolution of a tripartite system in Hilbert Space $\mathcal{H}_A \otimes \mathcal{H}_B \otimes \mathcal{H}_C$ when it is subject to two unitary evolution operators $U_{AB}$ and $U_{BC}$. $U_{AB}$ a unitary operator in $\mathcal{H}_A \otimes \mathcal{H}_B$ acting on the $A$ and $B$ ... |
I'm trying to prove equation (1.35)
$$\begin{align}
(\mathbf{a}\times\mathbf{b})^2 &=
\mathbf{a}^2\mathbf{b}^2 - (\mathbf{a}\cdot\mathbf{b})^2 \\
&− a_j[a_j,b_k]b_k + a_j[a_k,b_k]b_j − a_j[a_k,b_j]b_k − a_ja_k[b_k,b_j]
\end{align} \tag{1.35}$$
of lecture note "Angular Momentum" by B. Zwiebach
from "MIT OpenCourseW... |
Suppose two similar conductors which are unequally charged are brought close to each other,then charges from one will flow to another and ultimately both of them will be equally charged and either both will be positive or both will be negative.Now the conductors are separated.Suppose I draw a Gaussian surface as shown ... |
Like curvature of a geometrical shape, is there any purely mathematical explanation for what is mass?
Or is it absolutely a physical quantity in which case this question has no meaning?
I thought that mass might be a physical quantity but that it can be described in terms of something more fundamental i.e can be derive... |
I've started to learn Quantum mechanics and statistical mechanics on my own. There is a line in my book, which says, that
In an ideal gas, to remove the Gibbs paradox, the gas molecules are treated as indistinguishable. Since the molecules are of the order $10^{23}$, their wave functions overlap, and hence we can tre... |
so currently im learning about electricity and while im learning, i have some difficulties. i'm got really confused to understand the difference between electric potential with electric potential energy. but instead of asking the difference which have already stated in a lot of articles.
if object was pull by gravity s... |
I can completely accept that the internal energy of an ideal gas is the function of the temperature only, namely
$$U = \frac{f}{2} n R T$$
and that we can define 2 quantities ($c_v$ and $ c_p $) that can give the change in the temperature due to heat added when volume or pressure is held constant( $ dQ=mc_{\square} dT$... |
Apologies in advance for the size of the question. Apologies also for English, I read well, but I can not write well so I use a translator. I thank everyone who will answer me.
Guys, I started reading and watching videos about the observable universe (O.U.) and understood the whole part of the expansion of the universe... |
I am a bit confused about Malus theorem in optics ,as shown below : we consider a punctual light wave source , two light rays SB and SA , and two mirrors M1 and M2 placed respectively orthogonal to the bissectors of the angles (SA,Uz) and (SB,Uz), in order to make the reflected rays colinear to Uz .
By malus theorem :... |
I am trying to simulate a car engine etc, but I have failed to find any equations governing the torque created by $2$ different constant velocity shafts of different angular momenta joining together with some given slip or friction factor. I know $I_1w1 + I_2w_2 = I_3w_3$ which gives me the end angular velocities, but ... |
In a finite potential well like that in figure, is the potential constant between $-L/2$ and $L/2$? Since that energy is quantised, if I'm in the second excited state, would the potential still be constant and equal to $0$, so that energy is only kinetic?
|
I have read that behind the conservation of energy or momentum is the Noether theorem with its intimidating maths.
Is there any similar deeper foundation behind the conservation of mass?
|
Since the event horizon is defined as the boundary within which the escape velocity is greater than the speed of light, and escape velocity is the speed required for that object to reach infinity away from that point, why can't light escape the event horizon even if it doesn't reach infinity away from it?
I assume this... |
In the form, $$[J_i,J_j]=i\epsilon_{ijk}J_k\tag{1}$$ the Lie algebra of ${\rm SO(3)}$, denoted by $\mathfrak{so}(3)$, is called real Lie algebra.
By taking complex linear combinations $J_{\pm}=J_1\pm iJ_2$, $(1)$ can be written in the form $$[J_3,J_{\pm}]=\pm 2J_{\pm},~~~ [J_+,J_-]=2J_3.\tag{2}$$ Now, it is called the ... |
When two charged capacitors are connected(one positive plate with the other ones negative). I wondered since there is no electric field outside the capacitors, then why do the charges flow to balance out the potential of the two connected plates? Also if only one plate of a capacitor is connected with only one plate of... |
Is there a modern equivalent to the Landau & Lifshitz lecture series in theoretical physics?
I know the 10 volume series by Landau & Lifshitz is still relevant and very useful. But is there a more modern version that serves a similar purpose in providing the so called theoretical minimum for theoreticians?
|
A force between two particles can be described either as the action of a force field generated by one particle on the other, or in terms of the exchange of virtual force carrier particles between them.
These virtual force carrier particles are physically produced during these processes, like beta decay of neutron? Wh... |
I am currently studying the textbook Classical Mechanics, fifth edition, by Kibble and Berkshire.
In classical mechanics, we have that
$$m_1 \mathbf{a}_1 + m_2 \mathbf{a}_2 + m_3 \mathbf{a}_3 = \mathbf{0}$$
If we suppose that the force between a second and third body is such that they are rigidly bound together to form... |
There many proponents to teaching differential forms and others teach with tensors. This is true for both mathematics and physics education. It seems mathematicians prefer to teach differential geometry using differential forms. I want to know what is the current trend in theoretical physics, do they prefer to develop ... |
I'm studying identical particles and I'm thinking about something related to fermions. I have always heard that more than two electrons can't occupy the same energy level, because their spins are opposite and a third electron would have its spin oriented in the same direction of one of the other two. Now I'm studying t... |
I was flipping through Geometric Relativity by Dan A. Lee where on chapter $8$ the book proved spacetime positive energy theorem for $3\leq n <8$.
What happened to positive energy theorem for $n\geq 8$? Why it even matter to $n$ for this theorem, and that $n=8$ being a cut off?
(It kind of troubled a bit since yesterd... |
For a motion to be periodic must it have same amplitude over all time interval? Can a periodic motion have changing amplitude?
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Two identical charged spheres suspended from a common point by two massless strings of length l, are initially at a distance (x<<l) apart because of their mutual repulsion. The charge begins to leak from both the spheres at a constant rate. As a result the spheres approach each other with velocity v. Then v varies as ... |
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