# All Questions

1answer
81 views

### Engineering new particles

I am not a physicist, but I have a somewhat philosophical question regarding particle physics. In chemistry, and biology, there is a notion of synthesis, which has led to the creation of novel ...
0answers
37 views

### solution of a problem using divergent series [on hold]

are there examples of a physical problem whose solution is a divergent series ? i know CASIMIR EFFECT but i was thinking on aphysical problem so when you find the solution to this problem the result ...
2answers
77 views

### Why does the Earth rotate on its axis?

I know that the earth moves around the sun because of the gravity force, because the spacetime around the sun is curved. But why does the earth rotate on its axis, and which parameters can affect ...
2answers
61 views

### Can a Storm make the day longer/shorter?

I've read that changes in jet streams can affect the speed that the Earth rotates on its axis, thus making the day longer or shorter?
0answers
13 views

### how to specify eigenfunctions(eigentensors) of Lichnerowicz operator?

Lichnerowicz operator is an operator which acts on transverse trace-free symmetric tensors. If this statement is correct, my question is that any transverse trace-free symmetric tensor is an ...
0answers
49 views

### How to describe the motion of a box initially at rest on a table rotating with an increasing angular speed? [on hold]

Consider the following diagram. A box is on a table that can move circularly and the box is connected by a string attached to the fixed bearing. At $t=0$, the box is at rest, the string of length ...
4answers
559 views

### How Earth protected from the gamma rays generated by Sun?

Sun is generating energy by nuclear fusion. And nuclear fusion will emit energy in the form of gamma rays. Normally earth's ozone filtering the Ultraviolet radiation. And magnetic fields of earth ...
0answers
29 views

### Scintillator Length Calculations

This is sorta homeworkish, yet it still relates to my understanding of the physics behind it as well. Does anyone know how you determine t_98 (aka the length to contain 98% of the energy) for a ...
2answers
36 views

### Why the current decreases with increase in voltage in transmission lines? But according to Ohm's law current should increase with Voltage

Is the Ohm's law violated here? And also why is electricity generated at 11,000 V in India?
0answers
39 views

### Bell's inequality

For a project, I'm planning to study Bell's inequality, which as far as I can gather is taken to rule out hidden variable theories of QM. I'm looking for recommendations of decent sources which derive ...
1answer
65 views

### How Should I Think About the Dirac Equation?

In Weinberg's QFT Vol. 1 he says the Dirac equation is not a true generalization of Schrodinger's equation, that it does not stand up to inspection when viewed in this light. He says it should be ...
1answer
60 views

### Doesn't the second postulate of special relativity imply the existence of “luminiferous ether”? [on hold]

Einstein expressed his Second Postulate in On the Electrodynamics of Moving Bodies as: light is always propagated in empty space with a definite velocity $c$ which is independent of the state of ...
2answers
455 views

### Can a box on a frictionless rotating table rotate?

I am trying to digest the following problem. Suppose a block of mass $m$ lying on a horizontal, frictionless turntable is connected to a string attached to the center of the turntable, as ...
1answer
45 views

### Diffraction to be explained without Huygens principle

Can we explain diffraction without using Huygens principle?
0answers
11 views

### Teeter Todder force of uplift [on hold]

What is the force of a 200lb man jumping from a three foot high elevation onto a four foot long teeter-todder with a four inch pivot point with a one hundred and thirty pound ma on the opposite ...
1answer
33 views

### Draw a Schematic Diagram of Ammeter Connected in Parallel to explain difference between the diagram of a parallel and series connection

I know that voltmeters are commonly in parallel and ammeters are commonly in series. I believe that the voltmeters in diagrams 2 are actually in series. How am I wrong? In Diagram 4, I don't ...
0answers
10 views

### Electrostatics and Current Electricity [on hold]

A ball of mass 9 × 10^-5 kgs carries a charge of 5 micro coulombs. What must be the charge in another ball placed directly 2cm above the given ball such that they are held in equilibrium.
1answer
33 views

### Building blocks of particles in different theories

If I understand it correctly, in most theories in physics we exploit the notion of point, i.e. we have e.g. point-like particles. In string theory, we don't have points, but a notion of string. What ...
0answers
39 views

### Self-replication of gravitons in string theory [on hold]

How does the self-replication of gravitons work? Edit: Red Act says that prof. Luboš Motl could have meant self-interaction and not self-replication.
0answers
7 views

### Relation between size of obstacle, wavelength and diffraction

"If the boundary is merely an obstacle implanted within the medium, and if the dimensions of the obstacle are smaller than the wavelength of the wave, then there will be very noticeable diffraction of ...
1answer
64 views

### How does EM radition depend on the reference frame?

In special relativity, magnetism is electrostatics in a different reference frame. This is how we explain the magnetic field being produced by moving charges (aka currents). Charges that move produce ...
0answers
16 views

0answers
36 views

### In SUSY, why do fermions and gauge bosons in the same multiplet both transform in the adjoint representation of the gauge group?

I'm trying to understand a certain point about supersymmetry. We are dealing with a N=1 (i.e, one supersymmetric flavour), massless, four dimensional theory. Then the vector multiplet consists of a ...
0answers
14 views

### In the analogy of turning car wheels related to bending of light while entering glass through air, does that imply that two photons are “connected”?

There's a famous analogy that explains the bending of light when it enters glass from air. But doesn't that imply that two photons, represented by the adjacent wheels of the car, are connected by ...
3answers
66 views

### Reality of “electrical explosion”

I have often heard people who have been electrocuted refer to the "explosion" and how they were "thrown back" by the "blast". Sometimes the force of the blast is reported to throw people many metres. ...
2answers
127 views

### Why does “closing speed” $>c$ not violate relativity's second postulate? [on hold]

Why does closing speed $>c$ of a particle and photon or photon and photon not violate relativity's second postulate? Einstein expressed his Second Postulate in On the Electrodynamics of ...
1answer
29 views

### What would be the best way to explain color confinement in quarks? [duplicate]

To someone who is not so experienced in advanced physics, how do you explain or teach them why something as complex as color confinement prevents us from being able to see or prove that there are any ...
1answer
22 views

### Why the emf of a battery doesn't depend on distance between the two electrodes?

I have read that resistance of a conductor is directly proportional to its length...So ,the emf of a conductor(electrolyte of battery) should increase with increase in length/distance between the ...
0answers
7 views

### How do I determine the best fluid dynamics jet-nozzle design [on hold]

I understand the difference between an orifice and a nozzle in fluid dynamics, but what determines the optimum performance for a jet and what is the relationship between jet diameter and jet length?
0answers
11 views

### Why Nitrides have internal polarization?

Why GaN has internal polarization? I know that in wurtzite crystal structure, the atomistic bonds are not equivalent and as a result there appears a net dipole and consequently a polarization. But ...
0answers
11 views

### Applicability of Fano resonance

I know that Fano resonance$^{1,2}$ can be applied for the interaction between a discrete excited state, $|\phi_0\rangle$, and a continuum of excited states, $|\phi_E\rangle$. These are related to ...
0answers
17 views

### Newton's 3rd Law and Equilibrium [duplicate]

What is the difference between Newton Third Law and equilibrium?
2answers
64 views

### Newtons Third Law [duplicate]

In Newtons Third Law, it states that for every action, there is an equal but opposite reaction. So that means tat for every action, there will be a reaction to cancel it out. So if that is the case ...
3answers
116 views
+50

### Why does a conservative force return the work done against it by a body to that body?

Let a body move and a conservative force oppose its motion. Therefore, by Newton's third law of motion, the body will also exert reactive force on the conservative force which eventually will cause ...

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