4
votes
2answers
902 views

Is my interpretation of how a gravitational wave is formed correct?

I'm sure many here are familiar with the following image showing the 2D representation of how the fabric of spacetime is warped by the presence of mass:- Can this fabric be interpreted as an ...
1
vote
1answer
22 views

Right Hand Rule for Proton Magnetic Field

I thought that right hand rule was for find the magnetic field generated by a current, where your thumb point in direction of the current. However, I was watching something that said we can curl our ...
2
votes
2answers
33 views

How can we tell if a molecule is in thermodynamic equilibrium from scattering data?

We have a molecule that is emitting/absorbing photons. We know the Hamiltonian and that there are several levels. We count the emitted photons at different angles and frequencies. We can also do ...
0
votes
1answer
20 views

What does “shortwave radiation” mean to a meteorologist?

I'm have an empirical model developed using surface observations of radiation (400-1100nm). I tend to think of this as visible, near infrared, and a little bit of shortwave infrared. I now need to ...
0
votes
2answers
43 views

Charged particle singularity

Is it possible to manipulate magnetic/electric fields, similar to magnetic confinement technologies/penning traps, to compress charged particles into black holes?
0
votes
1answer
25 views

How is anti-hydrogen captured?

Knowing that the overall charge is zero, what mechanisms/technologies are used to capture anti-hydrogen? Where is it stored until annihilation? I am aware of magnetic traps being used to edge the ...
0
votes
0answers
22 views

Relativistic Doppler Effect and the Sagnac effect

What I think I know about the Sagnac effect can be found here. It occurs to me that the equations for calculating the time do not take the Doppler effect into account. I'm familiar with the very ...
2
votes
0answers
27 views

How do we 'watch ' atomic interactions?

I'm relatively new to objective physics and it's measuring and imaging abilities.. Specifically I don't know if we can 'watch' inter/or intra molecular exchanges like the photonic and electronic. I ...
1
vote
1answer
32 views

How to see the ground state degeneracy (GSD) from a $BF$ theory in $2+1$ $d$?

I have seen many times the $BF$ theory has non-trivial ground state degeneracy (typically on torus), but I can not see how the conclusion come out. Recently I found a paper by Hansson, Oganesyan and ...
0
votes
0answers
22 views

Circuit Diagram [on hold]

Three resistor are put into play, two in parallel and another in series to them. One of the resistors in parallel is decreased. what will happen to the voltage and current.
0
votes
0answers
38 views

How can light have the same speed for all observers? [duplicate]

I'm a little confused on this. If you're travelling at, say, 10% of the speed of light then light is travelling at 3x10^8 ms^(-1) relative to you. If you're moving at 80% of the speed of light and ...
1
vote
1answer
63 views

Interaction Lagrangian forms

When a charge motion is given (known), the electromagnetic field can be explicitly found (Retarded potentials, etc.). The interaction Lagrangian density is $j\cdot A$ or in the action it may look like ...
-3
votes
0answers
34 views

Theory on what would happen if a proton touches anouther [on hold]

I came up with a theory on what would happen if two protons touched each other. I want to know if it is scientifically valid. If two protons repel each other, then the closer you bring them together, ...
0
votes
0answers
26 views

Electric Field due to volume charge [on hold]

Electric Field at point P due to volume charge Since,the Electric field at point (0,0,z) is dE = ρvdvaR/4πε0R2 aR = cosα az + sinα aρ where aR means unit vector R can anyone derive the above ...
0
votes
0answers
34 views

Dry Ice Sublimation time, practical calculations [on hold]

I would like to send a parcel to a family abroad with frozen (to the temperature of -18 ° C.) products.The products are small balls having a diameter of 4 cm. Balls are made from pizza dough.Total ...
-3
votes
1answer
77 views

Why do we believe in a “force” driven universe? [on hold]

Why do we not believe in the potential for a "unified force field" universe, to the exclusion of the belief in the potential for a mechanical, gear driven universe, if the correct shape for the gear ...
1
vote
0answers
41 views

Is Ballentine's description of the Berry phase (in his book _Quantum Mechanics_) flawed?

Ok, so I'm looking at Ballentine's Quantum Mechanics right now, 7th reprint (2010). On page 363, he starts with 12.7 Adiabatic Approximation and quickly moves on to explain Berry's phase on page 365. ...
-4
votes
1answer
35 views

Why charge is an extensive property [duplicate]

While reading examples of extensive properties, I cam across electric charge. Can someone please explain to me why electric charge is considered to be an extensive property? We know that extensive ...
1
vote
1answer
41 views

Which inertial observer should I choose when using $\Delta U = -\Delta K$?

I just read and undertood that For any conservative force $F$ (which is not necessarily constant), we can define a potential energy change $\Delta U$ of an object on which the force exerts as ...
0
votes
2answers
46 views

What is the Weak force?

In this Particle Physics books I'm reading it explains Weak force with Beta Decay, a Neutron turns into a Proton after emitting an electron, so after it emits an electron one of the neutrons ...
1
vote
1answer
47 views

What does it mean by $t=-1$?

if the position vector of a particle is $\hat{r}=\left(4+3t\right)\hat{\imath}+\left(t^3\right)\hat{\jmath}+\left(-5t\right)\hat{k}$, i want to find at what time this particle passes through the point ...
0
votes
0answers
41 views

An inclined pulley system [on hold]

M1 and M2 both are 400g. There is no friction and the pulleys are massless. I am trying to work out the acceleration on M2. I am unsure whether the acceleration should be: $a\space =Mg\space -\space ...
0
votes
0answers
33 views

Action principles and covariant equations [duplicate]

Can every physically sound differential equation, that is covariant, deterministic etc. be derived by extremising a suitable action using a suitable lagrangian, that may be arbitary. Is this a ...
0
votes
0answers
40 views

Quantum decoherence and Schrodinger's equation

In non-relativistic quantum mechanics, the equation of evolution of the quantum state is given by Schrodinger's equation and measurement of a state of particle is itself a physical process. Thus, ...
1
vote
1answer
38 views

How to show that the force and velocity are perpendicular and that both have constant magnitude? [on hold]

The force acting on a moving charged particle in a magnetic field $\hat{B}$ is $\hat{F}=q\left(\hat{v}\times \hat{B}\right)$ where $q$ is the electric charge of the particle, and $\hat{v}$ is its ...
0
votes
0answers
18 views

joule-thomson effect and linde process

According to the j-t effect the decrease in the temperature is a result of the work done by molecule to expand thus increasing their PE and decreasing their KE, but in the linde process the next step ...
0
votes
2answers
36 views

Number of Orbitals - Hydrogen Orbital just one, but why can we plot also higher states e.g. SPDF orbits?

I am confused, hydrogen just has one electron in the 1s orbit. but why can we plot all kind of orbitals (higher energy eigenstates for that atom)? My assumption: So physically spoken these orbits ...
6
votes
1answer
67 views

Why is the Oort cloud spherical?

Having read up a bit about the Oort cloud hypothesis, I find I don't quite understand this. Why is the Oort cloud spherical while the rest of the solar system is disk-shaped?
0
votes
1answer
58 views

The “classical radius” of the electron [on hold]

According to one theory, the mass m of the electron arises simply as a consequence of the electrostatic energy of its electric field, through Einstein's famous expression ε=mc^2, where ε is the field ...
0
votes
0answers
13 views

Can the effectiveness of a heat sink be increased with surface texturing?

Some supercapacitors use chemical etching to increase their surface area by several orders of magnitude. Could a similar process be used on a heat sink to increase its surface area and thus its ...
0
votes
0answers
29 views

Wannier Hamiltonian in Momentum Space

In connection to a previous question, We can write the one-particle Hamiltonian in the Wannier basis working on a general vector $v$ as : $$ \langle\vec{R},\,\lambda|\hat{H}|v\rangle = ...
0
votes
2answers
27 views

Calculate expected Voltage at a distant electrode

Firstly, please forgive me for misconceptions and errors as my knowledge of Physics is very basic. I have EEG data (uV vs time) traces for an array of platinum electrodes placed on the surface of ...
0
votes
1answer
39 views

Energy Imparted by a Magnetic Field

My question is probably a bit low-brow for this forum, but here goes. As I understand it, when you switch on an electromagnet it generates a magnetic field which pervades all space, imparting ...
0
votes
2answers
30 views

How does the Earth's magnetic field interact with objects?

I'm not a physicist so I was wondering how objects and the Earth's magnetic field interact with each other. For instance: does any of them modify the other in any way? can an object be damaged by the ...
0
votes
0answers
13 views

How does a polarizing beam splitter work? [on hold]

How does a polarizing beam splitter work for a S-polarized or P-polarized beam?
1
vote
0answers
32 views

Places where fluid dynamical ideas show up in physics? [on hold]

One common theme of physics is that ideas and models developed to describe one type of physical situation are found to be nicely applicable to another type of situation. I know that fluid mechanics, ...
0
votes
0answers
12 views

how does a microphone on a hand held device select a specific speaker in a crowded room? [on hold]

I need a device that can focus on one speaker in a crowded room. Hearing aids fail this test. I need a primitive (physically) device that could clip on a belt and focus sound into earphones or ear ...
2
votes
1answer
36 views

entropy of a long molecule chain with respect to its length

Consider a (very long) one-dimensional chain of $N$ moleculs, which can be in either of the energy states $\alpha$ or $\beta$. The configurations have length $a$ or $b$ respectively. Show ...
0
votes
0answers
57 views

Is ohm's law violated in electric transmission lines?

Electricity is generated at a very high voltage say, 11,000 V... Does that voltage refer to the potential difference across the transmission line or does it refer to the electric potential at the ...
0
votes
1answer
25 views

Bubble pressure ascending?

In water bubbles rise up to the surface. As it rises, does the bubble's pressure decrease or stay the same? I think stays the same.
0
votes
1answer
55 views

Which moves faster in a time $t$: $A$ or $B$? [on hold]

Suppose we have two objects, $A$ and $B$, both made of the same substance. They also have the same shape (e.g. two spheres), but $A$ is larger and therefore more massive than $B$. Both $A$ and $B$ ...
0
votes
0answers
23 views

Conceptual resources for understanding Physics [on hold]

Before I ask my question, I would like to note that this is a request for resources, and not a question dealing with the principles of Physics. Conceptual tools help us bridge our perception, ...
1
vote
1answer
62 views

Is internal symmetry the same as gauge symmetry?

This is more a terminology question. I have seen that some people differentiate between the two types of symmetry: internal symmetry and gauge symmetry (of a field theory). Is there a difference (in ...
3
votes
1answer
49 views

Reflection of two electromagnetic waves

Can Electromagnetic waves be reflected by another electromagnetic wave without having any physical (transparent or opaque) material (i.e., in free space with one wave having twice the amplitude of the ...
1
vote
1answer
23 views

Shack-Hartmann wavefront sensor concepts, pupil conjugate planes?

I am just starting to looking at the application of wavefront abberommtery to measure abberations in the human eye. I am confused over the pupil conjugate planes, do you use relay lenses to image the ...
0
votes
1answer
40 views

Collision of a pendulum with other pendulums hanging at different heights

This is a question from a competitive test. I am not sure how to reason this out. By the length of the string, S should have the maximum amplitude. But this would be the case only when the pendulum ...
0
votes
0answers
10 views

What is the power of combination of an erect and an inverted halved convex lens?

So I have this question from a competitive exam. And I don't know to solve for the second part (I have a guess at the answer, but don't quite understand it). For the first part, focal length ...
-2
votes
0answers
10 views

What is the equation for plotting a graph for absorption in air as a function of wavelength(7.5micrometer-13micrometer)? [on hold]

What is the equation for plotting a graph for "Absorption in air as a function of wavelength(7.5micrometer-13micrometer)"?
2
votes
5answers
87 views

Relation between the conservation of Energy and the conservation of Momentum?

I just learn about the momentum and it conservative attribute in a closed and isolate system and there is something I don't understand when I relate it to the conservation of the energy Considering ...
0
votes
0answers
21 views

Thermal conductivity in gases

I've been musing about thermal conductivity and came upon the following question. Heat is transported through matter by molecules passing their kinetic energy onto other molecules, or simply by the ...

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