0
votes
0answers
4 views

What is the formula of power of a optical instrument?

I have across and have found that power of a lens with surrounding medium of refractive index n is n/f where f is the focal length, the formula n/f=(n'-n)/R1 + (n-n')/R2; But in book it is said that ...
-1
votes
0answers
12 views

How Space Curvature is proportional to Mass in G. Relativity?

In General Relativity, Einstein established that the gravity is due to the curves produced by objects in space. We all know that the gravity is proportional to Mass. The picture Einstein painted ...
-1
votes
0answers
12 views

Is it possible to cut the contents of an atom? (theoretical question)

For example, if I become the size of an atom and were to explore it. Then if I cut the proton, electron or neutron with a knife (remember, this is theoretical), what would happen? Would it blast, or ...
-1
votes
1answer
16 views

Zero vol. at zero Kelvin

Why the volume of a gas become zero at 0 kelvin?Can Bose einstein condensate be considered as a matter? (I mean the vol. becomes zero)
0
votes
0answers
9 views

Feshbach resonance in simple terms

I was reading up Feshbach resonances in cold atoms and I was unable to grasp the concept. I will tell you what I have understood. We consider two body scattering processes elastic as well as ...
-1
votes
1answer
13 views

Wave Equation - Vibrations & Waves

My question is basically how to do part ii) of this question even with the hint I am confused; the first part was simple; There's no dispersion & vp = vg = sqrt(hg) as required. But how would I ...
-1
votes
0answers
16 views

Optics modelling software

I am looking for software that could allow me to model the internals of my spectrometer. I would imagine some sort of ray tracer that allows me to add mirrors, slits, gratings etc. This way, I can see ...
-1
votes
2answers
30 views

Is it possible to travel ONLY through Time and not Space?

The question is as stated above. I although think, the most probable answer is no, but I really want to know the reason to it. If, One can travel through only space by travelling at the speed of ...
0
votes
1answer
16 views

Which of the Physics textbooks would you recommend I read this quarter (Analytical Mechanics)? [duplicate]

My Analytical Mechanics class this quarter has one required textbook: "Classical Dynamics of Particles and Systems" by Thornton & Marion and three recommended readings: "Mechanics" by Landau ...
0
votes
1answer
37 views

Inverse Square Law and extra space dimensions

Newton's famous Inverse Square Law says that in $3$ dimension of space, force is inversely proportional to the square of the distance between a source and a target. I understand that for higher ...
1
vote
1answer
25 views

How do you derive the Dirac equation for momentum space?

$\require{cancel}$ \begin{align} 0 &= i \gamma^\mu \partial_\mu \psi(x) - m \psi(x) \\ &= \int \frac{d^4 k}{(2\pi)^4}e^{-i k x}\left( \gamma^\mu k_m \tilde{\psi}(k) - m \tilde{\psi}(k) ...
0
votes
0answers
19 views

Simple question relating to physics prac reports

I am writing a physics practical report relating to the elasticity of materials relating to their momentum in a collision. I have values for the elasticities that are all within 2% of each other but I ...
1
vote
1answer
29 views

Why do really powerful magnetics have to be really big?

If you want to make a really powerful magnet, that can for example attract golf ball sized metal objects from 15 feet away, the magnetic has to be really big, and really heavy. Why is this so? I don't ...
0
votes
0answers
23 views

QFT Calculations via Holographic Duality

Holographic duality tells us that there is a duality between anti-deSitter space and lower dimensional conformal field theory. However, what quantum phenomenon, exactly, can we calculate using the ...
-1
votes
0answers
22 views

Gas Pressure in Industrial processes

Can anybody please help with the following? Ammonia is produced by the Haber process where nitrogen and hydrogen combine to form ammonia according to the equation: N2 + 3H2 == 2NH3 If 1 mole of N2 is ...
1
vote
2answers
50 views

What would a nuclear explosion look like at relativistic speeds where time dilation and length contraction become significant?

Suppose a rocket carrying a nuclear weapon is moving past our planet at very near the speed of light while a stationary observer watches from here on Earth. As the rocket passes directly overhead, an ...
-2
votes
0answers
25 views

Thermodynamics - Gas Laws

Can anybody please help with the following problem? The compression ratio of an engine is 16:1. The volume of air in the cylinder is $0.5 \,\mathrm{litres}$ at a temperature of $30 ...
2
votes
1answer
33 views

What are the tidal effects of Io on Jupiter?

I recall reading an essay by Asimov (I think) around 1980 stating that the tides are a function of a power of the diameter of the primary, so (surprisingly) small close moons of Jupiter raise large ...
2
votes
1answer
26 views

Is a rope wave a perfectly transverse wave?

When i create a disturbance in a rope.What is happening at the particle level.I imagine the particles and the forces on the particles like this: According to my model there should be some ...
-1
votes
1answer
37 views

Determine the equation of motion

The problem is the following. A ring of mass $m=1$ is moving along a circle of radius $R$ without friction. It's tied to a spring (coefficient $k$) of natural length $0$. The other end of the spring ...
1
vote
0answers
22 views

Flux Linkage Inside of a Conductor

Can someone explain to me why the flux linkage inside of a conductor is dependent on the cross sectional area of the conductor? My book says that d$\lambda$=$\frac{x^2}{r^2}$$\phi$. Where $\phi$ ...
0
votes
1answer
35 views

Would we see the past if we look to a mirror 1 light year away? [duplicate]

What would we see if we place a mirror 1 light year away? Would we see the present or the past?
1
vote
0answers
18 views

Hydrogen atom Ionization by Magnetic Field

The source of a magnetic field (it could be a magnetic dipole) is moving at relativistic speed. This magnetic field encounters a hydrogen atom at rest with respect to the source. Will this encounter ...
4
votes
0answers
61 views

Could Navier-Stokes equation be derived directly from Boltzmann equation?

I know how to derive Navier-Stokes equations from Boltzmann equation in case where bulk and viscosity coefficients are set to zero. I need only multiply it on momentum and to integrate it over ...
1
vote
1answer
41 views

Normalisation of a wavefunction

If the system if found in the state: $$\psi=\sqrt{\frac{1}{2\pi}}(\frac1{\sqrt3}e^{-i3\phi}+ce^{-i4\phi})$$ what value of $c$ normalizes the wavefunction? Clearly: $$\int_0^{2\pi}\psi^*\psi ...
0
votes
0answers
8 views

Ising model with metropolis algorithm around critical temperature

I'm trying to simulate Ising model using metropolis algorithm. Boundary conditions are periodic. I know how the algorithm works and I have written the code myself. Everything works as it should except ...
1
vote
1answer
58 views

Radiation pressure (Jackson exercise)

Here's an exercise from Jackson: A plane wave is incident normally on a perfectly absorbing flat screen. From the law of conservation of linear momentum show that the pressure exerted from the ...
0
votes
0answers
22 views

Why does the superconductivity hamiltonian have a µ term, while the superfluid does not?

In every discussion of SC and SF that I read (e.g. Simons), the SC Hamiltonian (BCS) has a $\epsilon_k - \mu$ in the kinetic part of the Hamiltonian, while the SF Hamiltonian has just a $\epsilon_k + ...
0
votes
1answer
34 views

Show that a solenoidal field is always a curl of a vector field

Can someone prove that: $$\nabla \cdot \mathbf{B} = 0 \implies \mathbf{B} = \nabla \times \mathbf{A}~?$$ I know that $$\nabla \cdot (\nabla \times \mathbf{A}) = 0$$ identically. But can one prove ...
-3
votes
0answers
21 views

Balancing an equation [on hold]

I had an exam today and I havn't be able to find an answer to the question asking to balance this reaction equation, about oxalic and permanganate. Could you balance it or is it just impossible ? ...
1
vote
1answer
22 views

Sufficient conditions for Equipartition Theorem to hold

I was wondering what are the sufficient conditions for the Equipartition Theorem. I know there is another question (For which systems is the equipartition theorem valid?) that somewhats answers this ...
1
vote
0answers
28 views

Would an undersea reverse osmosis station work?

According to Wikipedia, saltwater reverse osmosis occurs at 600-1200 PSI. Saltwater adds .455 PSI per foot, so 900 PSI would be at a depth of about 1980 ft or 603 meters. This is about halfway ...
2
votes
0answers
19 views

Problem on Einstein - de Haas experiment

I am a Physics student (4th year) and I'm trying to study the Einstein - de Haas effect in laboratory. That is what I got: a suspended Iron cylinder with about 5 cm height and a radius of 0.8 cm is ...
-2
votes
0answers
35 views

Establish a relation between height of the water column and time in a $spherical$ container with a hole in the bottom

Suppose we have half of a sphere of radius $R$ filled with water. In the bottom of the container there is a hole of area $S_0$. Velocity of the water flow out of the hole is $$V=\lambda(2gh)^{1/2}.$$ ...
1
vote
0answers
9 views

Thermodynamics of a heated enclosure

i have to maintain an aluminum enclosure of size 200x300x400mm at around 80 degrees Celsius, there for i need to calculate the thermodynamics of the system, ie what power of heater i need to achieve ...
0
votes
1answer
28 views

Solving Lagrangian equations of motion for two point-bodies with gravitational interaction

I would like to solve the equations of motion with the Lagrangian function for two point-bodies that interact gravitationally via the potential $$V= {-Gm_1m_2 \over r_{12}} $$ where $$r_{12} = **r_1 ...
-2
votes
1answer
53 views

Is there anything random? [duplicate]

Is there (in universe, wherever) anything random? Do we know any event (or whatever else) which has no reason? Of course there are some things that we cannot see, measure but it doesn't mean that they ...
0
votes
1answer
28 views

What's difference between C parity and charge?

I know C parity as an operator : $$ C\psi=\pm\psi $$ has two eigenvalues like parity operator P. But what I wonder is, i.e, is it true to say for a negative charged particle has (-) eigenvalue? If not ...
3
votes
2answers
44 views

Electric field due to a uniformly charged FINITE rectangular plate

I was teaching kids about how to find electric field using the superposition principle for continuous charge distributions, I thought may be I should derive the formula for electric field due to the ...
0
votes
0answers
35 views

How much water is needed for Saturn to float in?

Saturn floats because it's density is less than that of water. Just how much water would be needed? Assume a cuboid tank holding it. And when we actually put saturn in that water, how far in the ...
1
vote
1answer
26 views

What causes angular and linear deceleration in a sliding and rotating ring?

I was solving an AP Physics problem involving a ring sliding and rotating over a frictional surface. When I started to think about why the ring eventually comes to a stop I started to become confused. ...
0
votes
0answers
21 views

A magnet's magnetic field strength

Assume that we have six horseshoe magnets which are equivalent in every manner. If we put them together by stacking perpendicularly, what could be said about that magnet assembly in terms of its ...
2
votes
1answer
20 views

Microwave burns related to power per photon?

In wireless telecomunications we have multiple bandwidths being used nowadays: GSM 900Mhz and 1800Mhz, UMTS 2100Mhz, LTE 800Mhz, 1800Mhz and 2600Mhz, Wi-Fi 2.4Ghz and 5Ghz, (reffering to European ...
8
votes
2answers
986 views

Black hole with two singularities?

I hope this question isn't too naive, but would it theoretically be possible to have a black hole with 2 singularities (or 2 black holes at the same location). If this is possible, would there be any ...
3
votes
1answer
100 views

If we go to space why isn't the temperature high? [duplicate]

We know that the temperature in space (which has vacuum) is low. If I go to space will I feel sweaty and hot or chilly? I think I will feel sweaty and hot because the radiation (UV, IR, etc) of the ...
0
votes
0answers
9 views

Can an intercooler be analysed as any other heat exchanger?

I am doing this project on developing a code for the first and second law analysis of a practical Gas Turbine Cycle. It includes a two-stage compression process and thus, involves an intercooler, ...
0
votes
1answer
20 views

An equation for any charge distribution in a constant external electric field. Is it correct?

Is the equation (torque, $\tau = p \times E$) correct for any kind of charge distribution? (E is an external constant electric field.) If so, why? Will somebody prove it to me? I'm only sure of its ...
4
votes
1answer
42 views

Ground state for interacting field thoeries

Are there references where the ground state of an interacting quantum field theory is explicitly written in terms of states of the underlying free theory? For example, let us suppose to have a self ...
2
votes
1answer
28 views

Can we prevent metal corrosion by creating a vacuum around it?

I have a device in a box which has parts of metal. So can I prevent corrosion by creating a vacuum around the metallic object?
1
vote
0answers
12 views

Why can I feel the air inside the pump pressing against my finger when it is at 1 bar (atmospheric pressure)? [duplicate]

Atmospheric pressure is approximately 1 bar, but when I cover my bike pump with my finger and increase the pressure to 1 bar I can feel it pushing my finger away - how come? I'm guessing that what ...

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