# All Questions

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### Change in Wavelength of a Photon Relation to Energy (specifically Compton Effect)

Given a photon dropping from $\lambda_1$ to $\lambda_2$, its energy will drop from $\frac{hc}{(\lambda_1)}$ to $\frac{hc}{(\lambda_2)}$. However, I was wondering if there is any significance in the ...
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### Axisymmetric fluid flow

I'm having trouble with a boundary condition. In a fluid mechanics problem, I have flow at $z = \infty$ flowing into a solid plate at $z = 0$ and then flowing radially, and the problem is given as ...
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### Does the strength of a smell depend on the volume or surface area of an agglomerate of material?

I just switched from Timberland to Adidas shoes, and noticed a horrible trait of the Adidas tread: instead of being composed of externally-protruding bumps like the Timberland, it is composed of ...
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### Is a track in a cloud chamber made by one particle or many particles?

Is the track in a cloud chamber made by one particle interacting with many particles each emiting a photon or is the track made by many particles interacting on the same trajectory? or is it a cascade ...
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### Source of beating phenomena of a Michelson interferometer?

I was discussing the reason why we see beating from a Michelson interferometer, and one of my friend said it 's because the light have different frequencies, therefore, they would be out of phase. ...
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### Visible Lines for Hydrogen

Say H atoms are excited to 4th level, n=4 that is, how many lines do we see? How to decide the number of the lines?
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### Equilibrium - uniform circular motion

Maybe this is a bit of a silly question, but let us pretend we have a pendulum in a ideal universe with no friction, drag, or anomalous forces there to affect it. Additionally, our pendulum is ...
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### Yearly onshore wind turbine energy production [closed]

I am trying to work out the yearly energy production of an onshore Siemens SWT-3.0-101, hub height 94m, total height 144,5. Here is the power curve at each wind speed level worked out through a ...
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### How to find the phase constant? [closed]

I was given this velocity-vs-time graph of a particle in simple harmonic motion: I determined the amplitude to be $A = 1.15$ m, which Mastering Physics confirmed is correct. Then I was asked to ...
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### Atomic Orbitals, Singlets, Triplets

Why are singlet states representative of the S orbitals, and similarly why are triplet states representative of P orbitals? I learned about these states as resulting from having a total spin of a ...
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### Matter Waves Interference

When an EM wave diffracts, I can imagine that its EM field interacts with the charges in a certain obstacle thus inducing a wave behaviour on the charges of the matter that will interact with the EM ...
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### How can I calculate out the 'specific charge' of an atom? [closed]

I know that it's charge/mass. But what steps do I take to calculate the specific charge of say, carbon-12? What about ions too?
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### What defines the interaction strength of a particle (massless or not) with matter?

Generally, talking about photons, the shorter the wavelength, the higher the interaction with matter. I doubt that I really understand why this happens. What about other massless particles? And ...
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### Modeling sound resonance in an arbitrary cavity

I am trying to solve a challenging problem, and I'm hoping for some advice on how to proceed. I want to model sound waves in a cavity for the purpose of determining resonance. The plan is to answer ...
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### Is it valid to calculate mass of electron using the speed of the wave packet and energy

A gaussian wave packet. It's peak is moving at speed v. We know the energy of the packet is E. Can I deduce the mass of the electron using $m=2E/v^2$
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### Emf of a rod sliding on two conducting rails [closed]

The following is the question. Actually, I do not know how to find the answer. I have tried to find out the solution or hints from the lecture note given to me but it is quite difficult to ...
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### What really happens with Time Dilation? [duplicate]

I know if you move your time moves slower than someone who is stationary, by Lorentz's transformation. However, I don't get how this happens. What does it mean when time moves slower? How does it ...
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### Image formed in a compound light microscope

I am trying to understand whether the image formed in a compound light microscope is at infinity or not. I get conflicting answers everywhere I look.
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### Do electric fields generated by plane charges lose intensity over distance? If not, why?

Sparknotes' studyguide for the SAT II: Physics test says that for a point charge (1-dimensional, e.g. an electron), the formula for intensity of the generated electric field is given by ...
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### Force experienced on two particles in a rotating system?

I've a system of two particles of the same mass who rotate in a circle about the centre of mass of the two particles. Is the force experienced by the particles $F=MV^{2}/r$ or should I use ...
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### A question about electric field

I would like to understand why is it the charge density while dealing with currents is $\mathop{\mathrm{div}}(E)/4\pi$, while when dealing with insulators is $-\mathop{\mathrm{div}}(E)/4\pi$? Thank ...
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### Moment of inertia of a disc with masses attached at the rim

Does the moment of inertia of a disc with some masses attached at the rim be the same as one without the attached masses? Or is it necessary to use parallel axis theorem to incorporate the moment of ...
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### Normal reaction on wheels when car is taking a turn

I recently read in a book that for a car taking a turn on a horizontal surface, the normal reaction of the road on the outer wheels is always greater than the normal reaction on the inner wheels. ...
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### Are all elementary particles of the same type exactly the same?

Are all elementary particles of the same type EXACTLY the same? Is there some variation in what an electron is, for example, or are they all the same?
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### Want to achieve maximum magnetic force & find out the max point [closed]

Hi Sir/ Madam Want to achieve maximum magnetic force & find out the max point for this setting, want to know is the strongest magnetic force must in the 'dot' area ( middle poin of setting ) ...
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### Can matter be excited into energy and then be turned back into matter?

I was wondering the other day about teletransportation (human). And I had the idea that as far as I know, matter is energy. So I was wondering if it's possible to excite matter so it turns into ...
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### Why must the final state be stationary?

I faced the following sentences: We consider a gravitational collapse taking place in this spacetime. The singularity theorems assure us that a singularity will form. The assumption that the ...
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### Conservation of Angular Momentum and linear velocity

I have a problem where a cylinder is moving on a horizontal surface, starting with velocity $v_0$. It is given that its radius is $10\text{cm}$, its mass is $200\text g$ and the coefficient of ...
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### Air insulation cavity depth: rule of thumb to avoid convection

I want to know more about optimising an air gap between two surfaces, such as window panes or a building's walls. I was taught that as a general rule, a 6cm air gap is the optimum. Any larger and ...
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### Time dilation in a gravitational field and the equivalence principle

A clock near the surface of the earth will run slower than one on the top of the mountain. If the equivalence principal tells us that being at rest in a gravitational field is equivalent to being in ...
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### Concentration of photons: How many can you slow down in a given unit of space?

Being able to slow down light to the speed of a bicicle as shown in this vid: http://www.youtube.com/watch?v=EK6HxdUQm5s Led to a question: Given a unit of space e.g. 1cm^3, and then you slowed down ...
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### How Can There Be Magnetic Force Without Velocity [duplicate]

Suppose there is a space with constant magnetic field, and a charged particle is moving in that space with a constant velocity, ofcourse it experiences a magnetic force and gets deflected. But the ...
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### Will the heat flow of Joule heat be different, if the Joule heat is dissipated in a material that has a temperature gradient beforehand?

Let us assume one dimensional heat transfer, for example a finite length wire starting at point $0$ and ending at point $\ell$. If the current passes the wire, the Joule heat $I^{2}R$ will be ...
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### Exciting Surface Plasmons using ATR

I'm very new to the topic of surface plasmons and I have been reading about different methods of exciting them. There is one method in which a prism is set up to allow phase matching of an incident ...
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### Splitting of degenerate states due to perturbation

In band structures we see avoided crossing when we have degenerate eigenstates (caused by perturbation due to potential energy). However along some direction in first Brillouin zone, even though the ...
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### E&M question in example in my book [closed]

So I still not sure how to apply like Right-hand rule (RHR) in this setup in problem like the one in the following so I tried to do RHR in order to get the direction but it didn't work out. This is an ...
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### Missing centrifugal acceleration

I am trying to get correct equations for acceleration of a point in reference frame A, given position, velocity and acceleration in rotating reference frame B. Let $\mathbf{x}_A(t)$, ...
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### Is it possible for a material to have a polarization field greater than the applied field?

In the case of a dielectric (LIH at least, since that is all I've studied), the polarization field is always less than the applied field. In the case of a conductor, the polarization field is equal ...
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### Wave packets and the derivation of Schrodinger's equation

I studied in my class, that a plane progressive wave cannot be used to represent the wave nature of a particle as it is not square integrable. Also, the phase velocity can get above the value of $c$, ...
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### Discord for partially decohered bell state

To illustrate discord and its use, Zurek in his paper on discord (NB pdf) gives example of a partially decohered bell state i.e. \rho_{AB}=\frac{1}{2}(|00\rangle\langle 00|+|11\rangle\langle 11|) + ...
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### Probability in Quantum Mechanics: General

How do I find the most probable value of position of a (non-Gaussian) wave function? Is it the same value as the expectation value of the position? And is it true that the most probable value of ...
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### Write a parabolic equation in kinematics

How might I go about writing a parabolic equation in standard form $ax^2 + bx + c$ given all of the following measurements: $X_0, X_f, Y_o, Y_f$: the initial and final x and y positions. ...
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### Can the phrase “Terminal Velocity” be used to describe non-gravity situations?

According to Wikipedia: [Terminal Velocity] is the velocity of the object when the sum of the drag force (Fd) and buoyancy equals the downward force of gravity (FG) acting on the object. Since ...
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### Partition functions in $\phi^{4}$ theory

The partition function in a $\phi^{4}$ theory is written Z[J]=\int D\phi \, e^{-\int d^{4}x \left(\frac{1}{2}\left[(\nabla ...
In my introductory physics class, $V$ is the symbol for electric potential (joules per coulomb) and $U$ is the symbol for electric potential energy (joules). Since the Schrodinger equation is the ...