Physical Definition and 1000 Threads

I have a capacitor which I would like to know if the dielectric has undergone dielectric breakdown. Is there anyway I can tell without specialist equipment, is there physical damage to the material that I can see with the naked eye? The material is quartz. Thanks.

Can you tell any physical properties of a Messier object by its name, such as M1 or M42? I know this may sound like a silly question, but I am doing an Astronomy GCSE and I thought that maybe there was a better way of just looking it up online and remembering it. Thanks.

Homework Statement Determine the maximum kinetic energy of a uniform rod of mass 0.5Kg and length 0.75 that has an angular displacement of 5 degrees. Homework Equations y = rsin (x) where x is the angular displacement The Attempt at a Solution Using conservation of energy ETotal = EMech +...

Just wondering what the physical size of amino acids such as glycine and alanine are in nm or Angstroms. Thanks.

I'm currently in my first year of a MSc in physical chemistry and in the process of deciding what topic to choose for my thesis (most likely starting around april). I think my personal interests lie more on the side of physics than chemistry (I have only become sure of it this year). My...

Things like light waves and radio waves move at a similar speed. So in stead of saying radio waves travel at the speed of light, which is true, saying "the speed of information" also makes sense, because that's basically the univeral limitation for information to travel. However, I've heard...

I have been told that phase transitions=physical equilibriums. How can phase transitions be physical equilibriums? For example, if you have liquid water going into gas phase, doesn't delta G have to be greater than 0 for the phase change to occur? Is physical equilibrium an assumption in phase...

explain the physical meaning of img . part of signal

Can you give me some links, how to write a physical paper, for instance about theoretical physics. I found a book "Science Research Writing for Non-Native Speakers of English" written by Hilary Glasman-Deal, but it is more general, not only for theoretical physics.

We talk about local effects and surfaces being "in contact" with one another but do we have a vigorous definition for such a state? The objects reach a distance where their repelling EM charges resist and balance against a given force (such as gravitation)...but increased charges would make...

Homework Statement I am in Intermediate Electricity and Magnetism, and am working on review problems. I have a potentially very silly question: What physical direction is "horizontally north" (and similarly "horizontally south")? This seems like a counter-intuitive description to me (90...

I searched for, but could not find any name or published value for a constant (with units m-3 K-3) which when multiplied by temperature (in degrees Kelvin) cubed gave the corresponding photon density (in m-3). Does anyone know of such a constant with a published value? I calculated a value, but...

Does the Lagrangian L in classical mechanics have any physical meaning? In classical mechanics, the Lagrangian is defined as L=T-V, the difference between the kinetic and potential energy of the system. Does this quantity have any meaning apart from that it can be plugged into Euler-Lagrange's...

I'm currently a freshman a MIT. I was planning to do a Chemistry and Physics double major but after looking at the requirements for a Chemistry minor, it wouldn't take any additional classes to do a Physics and Math double major with a minor in Chemistry. The reason this is appealing to me is...

I have heard that ST can calculate the masses of the particles species of some vacuum and also its decay rate, charge and so on, but I have not seen any clear paper on the subject. Can anyone point me to one? Are "hbar" and "c" the same in all the vacuums?why or why not? Can ST predict the...

Hi, I'm trying to make sense of a wave propagation problem. It's a 1D problem, modelling propagation of density perturbations which travel like waves in a fluid. The problem is governed by the mass and momentum equations and density is related to pressure using the bulk modulus of the fluid...

Both Hawking and Dyson have said that Godel's incompleteness theorems prove that it is impossible for us to formulate an absolutely fundamental Theory of Everything. Is that true? Do the theorems apply to the physical world as they apply to the realm of mathematics?

Both Hawking and Dyson have said that Godel's incompleteness theorems prove that it is impossible for us to formulate an absolutely fundamental Theory of Everything. Is that true? Do the theorems apply to the physical world as they apply to the realm of mathematics?

Consider this self-evident proposition: "If object A has the same mass as object B and object C separately, then object B has the same mass as object C." Why isn't this stated as a law, but the zeroth law of thermodynamics is? Is there a physical quantity u such that the u of A is equal to the...

In, QFT, an elementary particles is an excitation of its quantum field. Quantum fields are just mathematical. For example an electron is excitation of the electron field. But is the excitation of the field physically real or just mathematical? What i mean is, is there something physically...

From P. Meystre's book elements of quantum optics (Many labels of equations are wrong:H) Page 83, the annihilation operator and creation operator, which are helpful to discuss harmonic oscillator, are defined as ## a=\frac{1}{\sqrt{2\hbar\Omega}}(\Omega q+ip),\\...

I have to say that I am a bit confused with the use of complex numbers. I know that: 1. They have been created by mathematicians to solve the "real"ly unsolved equation of x^2=-1. 2. They are used in many aspects of physics, like waves and quantum theory, with terrific correspondence to the...

This has been in the back of my head during a course in Mathematical Physics. In for example cylindrical or spherical coordinates, we have one or two unit vectors describing position (er, for example), their directions in a Cartesian system the function of three variables. But we also have e.g...

What physical interpretation can we draw from the thermophysical property of thermal diffusivity? How might we visualize the true physical meaning of this property and relate it to its definition?

Guys I want to ask that on surface of water there are unbalanced forces in downward direction so adsorption takes place so how they balance the forces in downward direction? I drawn a free body diagram but I still got a force to water molecule in downward direction so how that molecule is stable?

For the problem of particle in a 1D box V(x)=0 for 0≦x≦a ∞ for anywhere outside the box I know that Hamiltonian operator commutes with momentum operator so they should have smae eigenfunction but it's obvious that the wavefunction (2/a)^1/2sin(nπx/a) is not a eigenfunction of linear...

Homework Statement Homework Equations see picture above The Attempt at a Solution I can follow most of the steps, but not all. I got confused with finding ##|\frac{dz}{dt}|##. It is easy to derive ##\frac{dz}{dt}## from ##z##. Normally, I would square the two components of ##dz/dt## and...

Homework Statement For the reaction CH3OH(l) → CH4 (g)+ 1/2 O2 (g)[/B] (a) Calculate ∆Ho298 (b) Calculate ∆Eo298 (c) Write an equation that would allow you to determine ∆H at 500°C and 1atm Homework Equations ∆H=∆E+∆(PV) ∆H=Σ∆Hproducts-Σ∆Hreactants The Attempt at a Solution a)...

This is actually for a wood shop project... but it certainly involves geometry! I am trying to build a real-world regular icosahedron. I know I need 20 equilateral triangles for the faces. But I do not know what the angles of the sides/thickness should be, to join those 20 triangles into a 3D...

So if we become a Kardashev type II civilization, able to harvest all the energy and matter in the solar system what could we see through the massive telescopes that would be possible to construct? (say with a lens the size of Saturn). Could you get surface detail on extrasolar planets, for...

Is there some kind of intuitive way to understand the physical meaning when mathematical operations are applied to equations in physics? What I mean is that, say we start with a 'starting point' equation, in this example Ficks law of diffusion (wikipedia:): J = -D \frac{\delta \phi}{\delta x}...

What is physical interpretation of velocity potential? Is a conservative quantity, i.e, line integral of velocity potential around a closed loop is zero>

If an ODE of 2nd order like this A y''(x) + B y'(x) + C y(x) = 0 has how physical/electrical interpretation a RLC circuit, so, how is the electrical interpretation of a system of ODE of 1nd and 2nd order? \begin{bmatrix} \frac{d x}{dt}\\ \frac{d y}{dt} \end{bmatrix} = \begin{bmatrix}...

Hey PF! 1. Homework Statement If I have a pendulum; a vertically hanging rod with (length ##L## and mass ##m##) which can rotate freely about a point ##p## on the upper edge of the rod. Now I fire a bullet (also with mass ##m##) into it (strictly horizontal on the lower end of the rod). I...

All the physical simmetries implicate an automorphism in axioms. But ¿all the automorphisms from a physical equation do implicate a simmetry?

I always wondered that what is the physical interpretation of integration . How come integrating position gives as velocity? Can some one explain me what is physical insight of integration ? Ignore my poor communication skills.

I saw many books on physical chemistry by Peter Atkins. 1)Elements of Physical chemistry by Peter Atkins and Julio De Paula 2)Physical Chemistry by Peter Atkins and Julio De Paula 3)Chemical Pricnciples - A quest for insight by Peter Atkins and Loretta Jones Which book should I use for learning...

Hello ppl ! If i find that a physical quantity (lets say angular momentum operator vector L) is conservative (this means [H,L]=0 - H=hamiltonian ) then its 3 components Lx , Ly and Lz are being conserved too ? That happens with every conservative vector operator ? Like spin vector S and his...

My professor in Classical Electrodynamics is great and all, but sometimes he has trouble understanding what it is that I don't understand. So here I am. Let's say we have the some sort of (monochromatic) radiating system generating a electric field with Fourier amplitude Eω(x) and want to...

just finished Susskind's QM. Definitely blew my mind. Can't stop wondering about commutators. Trying synthesize and remember with self quiz I can't self grade. Super quiz: Could one in principle calculate the number of Planck flops (commutaor operations or bits) in a human lifetime? My...

Hey! How are the two m=0 spin states (<up,down> + <down,up>) and (<up,down> - <down,up>) physically different? I realize that according to the math, the first one has a total spin of ##2 \hbar## while the second has a total spin of ##0##. But wouldn't you, intuitively, expect both states to...

Hi all! Where are some good places on the Internet where I can learn about physical cosmology? Specifically any good websites that are devoted to physical cosmology that you know about?

I want to know what exactly Eigen value imply. What is its Physical significance ? Physical significance of eigen vector? Does eigen value concept apply in signal processing or evalvating frequency response off a system?

Homework Statement I have a physical pendulum made of a leg which mass is ignored, with a length of 1m, two objects of mass are placed on the bottom and the top of the leg, the first with a mass of m1= m1, and the second with a mass of m2= 3m1, both are L/2 away from the pivot point. It's...

I have very simple questions. Although these are simple but I am confused. So if I start with a lagrangian of the following form $$ \mathcal{L} = \partial^{\mu}\phi \partial_{\mu} \phi^{*} -m^{2} \phi^{*} \phi $$ then I get a current for the global invariance of the lagrangian and that is of...

I originally posted the following question on physics.stackexchange, but no one was able to answer it. I did find this answer on PhysicsForums, but I was already aware of the oscillation of electrons in response to an external electric field. What is the physical cause behind a material having...

Homework Statement You are at a furniture store and notice that a grandfather clock has its time regulated by a physical pendulum that consists of a rod with a movable weight on it. When the weight is moved downward, the pendulum slows donw; when it is moved upward, the pendulum swings faster...

what is Physical significance of Enthalpy for a process where we don't have pressure constant

Do we understand how the physical laws of the universe created biology? How can we explain cell division, consciousness, evolution, as a product of matter operating in a universe governed by laws?

Homework Statement Check on labb41.jpeg (I am not used to formatting my mathematical equations on the web, I can only format in my local text-editing programs). Homework Equations Again, check on labb41.jpeg The Attempt at a Solution I have plot the solution to U(I) as according to the...