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Dear all. I would like to know the general expression of the ratio of the electric field strength E to the magnetic flux density B. I know E/B = c, where c is the speed of light, for a vacuum, but I want to know if this is stil valid for any material where the electric and magnetic fields are...

Hello. I've been really curious about how TFP (Thin Flim Polarizer) works. I've searched TFP information through the Internet which tells that TFP utilizes Brewster's angle. This explains how the P-polarization transmits TFP with 100 % transmission, but I don't know how the S-polarization is...

Hello. Thank you for giving me the explanation. I thought the electron cloud fluctuation occurs even at completely isolated ground state neutral atom. However, you said such a fluctuation occurs only when there is external interaction with it. So, for the isolated atom in the ground state, the...

Hello. What I know about the Van der Waals force is that it comes from an instantaneous electronic cloud flucutation of the netural atom. This instantaneous electric dipole of the atom attracts electrons in nearby neutral atoms so other electric dipoles are induced on those atoms. As a result...

Thanks you! you and Chestermiller suggest examples of a quasi-static and irreversible process. I've searched the internet and found that the reversible process is quasi-static but its converse is not guaranteed. So, I think the definition of the reversible process given in my book has some hole...

Hello. I read the textbook of the thermodynamic and it said the definition of the reversible process as "thermodynamic process which is slow enough so the system state is always infinitesimally close to the thermodynamic equilibrium (quasi-static) during the process. Such a process can always...

Hm...I got some idea right now. The force –Fpg may not be taken into account in a calculation of the work done on the piston since the origin of this force is the piston itself; the work with –Fpg on the piston may be the work done by the piston itself via the reaction force. It is reminiscent...

Hello. I really don't want you to be bothered; But..why is -Fpg same to Fpres ? I think they're different entities. Fpres is from the collisions of gas particles on the piston bottom wall, while Fpg is from the state that the piston is pushing the gas downward. Their origins are different, so...

I appreciate your kind comment:) I would like to simply accept your force balancing on the pistol; your drawing really fits what the thermodynamic textbook try to explain. However, I'm still in trouble. Let's have an extension of your drawing. Here, there is another force on the pistol from...

Hello. The entropy S is a state variable or state function as the integral of dS = dQ/T is a path-independent, provided that the path is reversible process path. However, such a path-independency of the integral breaks down when the path includes irreversible process. So, I guess we can only...

I see. I think I finally got the right answer. Thanks for all of you to guide me along a right track! I attached the summary of what I've learned from your answers and I hope this would helpful for other guys who have similar question.

Hello. I think you suggested me a way to break through my confusion. Yes, the piston is receiving forces from two things simultaneously; one is the external agency pushing the piston by the force Fe, and another one is the gas pushing the piston due to Newton's 3rd law Fgp (external agency...

Hello. First, look at the figure describing Carnot's cycle. In 1st step (A → B) and 2nd step (B → C), I fully understand that the work done on the pistol (surrounding) by the gas (system) is dW = pdV where dV = Adl since F = pA is the only force on the pistol from the gas (I assumed there...

Hello. I'm sorry but I don't understand your geometry. The circumferential magnetic field around the conductor will induce a voltage on another wire which is in parallel oto the first conductor? This EMF is very different than what I'm used to such as a solenoid coil so I don't get how EMF is...

Hello. I'm using CT (Current Transformer) to measure the current flowing on the power line. The frequency of the current is 13.56 MHz. CT appeared to be metal-shielded (This metal case of CT may be grounded when CT is used). CT has a toroidal shape and the power line under the measurement...

Thanks for giving many comments on my question. Especially, I appreciate Jim's consistent comments on me:) The last comments you and Badadag made are something I need to take some time to consume. I'll give anything on this post If I come up with some idea regarding this.

Hello. I've summarized an inductor in my own material which is now uploaded here. On the inductor coil, there is not only EMF-field but also an electrostatic field. In principle, the line integral of a sum of these field along the coil gives a potential difference or voltage on the inductor...

Hello. Let's say a current i(t) flows through an inductor of solenoid type. Time-varying i(t) generates a magnetic field B(t) inside the magnetic core of the inductor. As B(t) is time-varying, EMF, which is the line-integral of the induced electric field E(t) along a coil (which carries i(t))...

Hello. Resistive Ohm's law is famously known as V = IR. We can derive its microscopic version as being followed. V = El, where E and l are, respectively, an electric field and a resistive load length over which a voltage drop V is developed. I = JS, J and S are a current density and a...

Thanks for replying very quick comment! So, E or B-fields in Maxwell's equations are all the same one, in fact. Could you help me a little bit more? I actually want to derive that RHS of \nabla \cdot E = \frac{\rho }{{{\varepsilon _0}}} is zero when E-field here is E-field accompanied with...

Hello. I would like to ask one simple question. Do we need to distinguish E-field (Electric field) in Gauss's law from those in Maxwell-Faraday equation and Ampere's circuit law? I firstly thought that E-field in Gauss's law is only for electrostatics so I need to distinguish it from E-field in...

Hello. I really appreciate your help! I've summarized what I've studied for the relation between Faraday's law of induction (or simply called Faraday equation) and Maxwell-Faraday equation. I found that the Faraday equation describes not only Maxwell-Faraday equation, but also magnetic Lorentz...

Hello. Let's take a transformer picture first. The basic equation explaining how the transformer work is the equation of Faraday's law of induction. \begin{array}{*{20}{c}} {{V_P} = - {N_P}\frac{{d{{\rm{\Phi }}_B}}}{{dt}}\;\;\;\;\left( 1 \right).}\\ {{V_S} = - {N_S}\frac{{d{{\rm{\Phi...

Hello. Thank you for a quick reply! Well..in 2nd answer, how to derive the original Faraday equation from the differential form of MF (Maxwell-Faraday) Equation? Applying stokes' theorem to this MF equation only gives MF equation in an integral form where ∂/∂t is inside the integral, while the...

Hello. I have several confusions regarding Faraday's law of induction. EMF = \int_{}^{} {\vec E \cdot d\vec l} = - \frac{{d\Phi }}{{dt}} = - \frac{d}{{dt}}\int_{}^{} {\vec B \cdot d\vec S} . It means that If the magnetic flux Φ through the closed conducting loop changes in time, electric...

Please never mind. "Pure active" just means that the power on Zeq has no reactive power, it only has an active power. The original sentence I made was right. I was trying to emphasize a difference between an active power and a reactive power. Thanks for giving me some advice. I'll consider...

Hello. Thanks for giving comments. I think I need to think this problem more carefully, before asking further and further. However, in order to start right reasoning, I need to confirm one thing: In impedance matching by adjusting CT and CL so that Zeq = RS, a power dissipated in Zeq is P1 =...

Hello. I'm sorry but phase? Do you want me to write phase of ..impedance? I'm talking about general case so a specific phase is not relevant. And what do you mean > and < ?

Hello. Thanks for giving a quick answer:) I'm sorry but I'm afraid I couldn't get your point yet. I know how the transformer works and it seems that you're equating any complex network with a load ZL = RL + iXL to some ideal transformer with a load RL in its secondary side. I don't know how...

Hello. Please looks at the attached image first. The left image is LCC impedance matching network (one of T-type impedance matching networks) and the right is the corresponding equivalent circuit when CT and CL are adjusted such that an equivalent impedance of the sub-circuit surrounded by...

One-cycle-averaged power is conveniently calculated by using complex representations of voltage and current such as \tilde S = \frac{{\tilde V{{\tilde I}^*}}}{2} = P + iQ, where P and Q are an active and reactive power respectively, and absolute value of S is an apparent power. Here, I choose...

I didn't fully read your question as formulas are not tidy. Please look at my attached material which might help you, I think.

Hello. I'm trying to do my best to explain your question. I can be wrong:) By rubbing a glass rob with a silk, some electrons in the rob transfer to the silk due to different electronegativities of both materials, I guess. As a result, the rod becomes positively charge as it has a lack of...

Hello. Thanks for giving very quick answer! So equivalent impedances are always important in impedance matching problem, even for a circuit with a transmission line, right? Let's assume rather high frequency and long length of the transmission line between A and B. So, in the case of Zin ≠ ZB ...

I see. Now I almost accept the fact that total or equivalent impedances are important, rather than impedances of individual electrical components in a circuit when we concern an impedance matching problem. However, for circuits connected with a transmission line, I have one confusion. Let's say...

Yes, the circuit A can be seen as the ideal voltage source with some series impedance ZA, according to the Thevenin's theorem. Maybe I'm questioning what it is obvious for others. Here, the impedance matching problem may only concern ZA and ZB which is an equivalent impedance of the circuit B...

Hello. Please look at the attached image first. There are two circuits A and B which have individual electrical components a and b. Components a and b are electrically and directly connected by the red lines. Impedances of individual components a and b are not matched, however, equivalent...

I'm studying experimental plasma physics in South Korea as a Ph.D. student. I'd always been curious about particle physics, relativities and math but I'd never considered to study them seriously, until taking these classes in last semester. I'm already 32 years old in Western age count so I want...

Hello. I'm actually taking Ph.D. course for plasma physics and I think I'll finish this course within this year. I took classes in quantum field theory and general relativity in last semester luckily and experience of these subject ignited a desire to study theoretical particle physics and...

Hello. I think I finally get an answer to the question. I'm uploading my summary of Racah and Paschen notations here everyone having the same question will benefit from it.

Oh, Yes. You're absolutely right. I was confused. Yes, for two electrons in a partially filled subshell or different subshells or even free states, we really don't know a definite value of total spin projection quantum number ms for these electrons before its measurement, unlikely to CS (Closed...

Hello. I found and studied a simpler proof of existence (always exist) of a set of common eigenfunctions for commuting operators in degeneracy. I uploaded this so other people who have a similar question can refer.

Am...I'm afraid that my statement gives a possibility of wrong interpretation. In my statement of "for compatible (commuting) operators {A, B}, we can always find a set of common eigenfunctions of all eigenvalues of both operators", "eigenfunction of all eigenvalues of both operator" does not...

Hello. Your answer is far more complicated than I expected. It was a long time ago that I studied matrix representation of operators. But of course, I'll re-study this for reminding to understand your comments. Before doing that, I just want to gett an answer of one question: is statement of...

Hello. I read the textbook and found that common eigenfunctions are even possible for degenerate eigenvalues. Let's say operators A and B commutes and eigenvalue a of operator A is N-fold degenerate, means that there are N linearly independent eigenfunctions having same eigenvalue a. These...

Hello. I appreciate your effort to follow all kinds of questions that I have posted. Thank you. Right now, I'm thinking that the question about "pairing electrons in a PS (Partially filled Subshell)" doesn't make sense at all. We're talking about angular momentum (and spin)-related total...

Thanks for giving me some answer. Let me summarize your comment. So, the fact that the total orbital QN (Quantum Number) l for CS (Closed Subshell) is always zero stems from a requirement that total magnetic QN m is zero for CS; no other value than 0 is allowed for m (a sum of individual...

PeterDonis indicates same things as you mentioned. I would be happy if you follow his last post and my last reply to him and give me some comments:)

Oh Yes! You're touching the heart of my confusion! I thought that CS (Closed Subshell) and the situation that all electrons are paired are equivalent. "electrons are paired" here means that if there is an electron with an individual magnetic QN (Quantum Number) mli = a and individual spin...

There is a thing that I was wrong in my question. In the Paschen notation nl#, n is even not same to the principle quantum number of the excited electron! So, I have to ask additional question of what n really is. The Paschen notation really makes me crazy.