How is light slowing down in a medium thought of in the photon picture?

What is the mechanism behind the slowdown of light/photons in a transparent medium?


Is gravity weak negative electric charge?

Is gravity just electromagnetic attraction?


What is time, does it flow, and if so what defines its direction?


What are the various physical mechanisms for energy transfer to the photon during blackbody emission?


Why does a wind turbine have only three blades?


What are the dimensions of the stress energy tensor in relativity?

Intuitive understanding of the elements in the stress-energy tensor


Why intensity of light(wave) is proportional to the square of its amplitude?

Exact relationship between electric field and intensity


Can de Broglie Waves have frequency, just because we know de Broglie wavelength formula?

De Broglie wavelength, frequency and velocity - interpretation


Is gravity's acceleration rate - squares of all natural numbers?

Question Based On Galileo's Law Of Falling Bodies


Why don’t objects approaching the speed of light form a black hole?

If a mass moves close to the speed of light, does it turn into a black hole?


Why is gravity so hard to unify with the other 3 fundamental forces?


How can magnetic fields have energy and yet be unable to do work with that energy?

How can magnets be used to pick up pieces of metal when the force from a magnetic field does no work?


Does Quantum Mechanics need imaginary numbers?


Why is spacetime curved by mass but not charge?


Why can't we resolve the velocity along the direction of movement of the mass in the first place?

Why is velocity of the mass $v/ \cos θ $? Why not $2v \cos θ$?


Any good Cosmology book recommendations (undergrad->postgrad level)


How is Gauss' Law (integral form) arrived at from Coulomb's Law, and how is the differential form arrived at from that?


Why do we replace $c$ (speed of light) with $v$ in de Broglie's equation?

Proof of de Broglie wavelength for electron


Why does the pitch of an ice cube hitting against the side of a glass increase as the glass empties?

How and why does the height of water in a glass affect it's resonance? (resonant frequency)


How do you interpret the radian in physics?

Are units of angle really dimensionless?


Why is the net angular momentum of Solar system not zero?

What causes matter to initially rotate/spin/orbit?


Theoretically, how could a wormhole be made?

Can a wormhole be created if it has not always existed?


Mathematical prerequisites for classical (Lagrangian and Hamiltonian) mechanics

Prerequisites for classical mechanics by Susskind


I'm confused about two aspects of quantum mechanics: 1.probabilistic nature of quantum 2.time evolution operator

Is the universe fundamentally deterministic?


What is the Lowest point of gravity on the Earth map?


Why is an alpha particle 'specifically' emitted in radioactive element and not other some other particle?

Why are alpha particles such a prominent form of radiation and not other types of nucleon arrangement?


Does the engine's thrust not contribute to the lift?

Does the engine provide the lift of the aircraft?


Physical meaning of this integral in $k-$space

Physical meaning of this integral in $k$-space


Why redshift of light occurs between galaxies only?

Why does space expansion not expand matter?


Would a group of molecules in a container, settle down after a long time? (considering that no gravity acts on them)

How do gas molecules constantly bounce without losing energy?


Quantity conserved for the 3D spherically symmetric harmonic potential $V(r)=\alpha r^2$

Is there an analog to the Runge-Lenz vector for a 3D spherically symmetric harmonic potential?


Why are the orbits of planets in the Solar System nearly circular?


Schrodinger equation using relativistic kinetic energy

What's wrong with the square root version of the Klein-Gordon equation?


Understanding the concept of surface tension


Are there any physics equations that involve exponents >= 5?

Are there any physics formulas with high/large exponents?


How sun gravitational field changes the rate of flow of time on earth

Does Earth experience any significant, measurable time dilation at perihelion?


Are there any liquids with zero surface tension?


Does quantum entanglement imply a universal "now"?

Why is quantum entanglement considered to be an active link between particles?


Interval preserving transformations are linear in special relativity


What is the analog between charges and mass with regards to vector fields?

Can all fundamental forces be fictitious forces?


Two body problem - Orthogonal trajectories

Calculating gravity when taking into account the change of gravitational force


What's need of infinite divisibility in our mathematical calculations, if Planck length/time is smallest value?

Does the Planck scale imply that spacetime is discrete?


Do photons actually slow down in a medium, or is the speed decrease just apparent?

What is the mechanism behind the slowdown of light/photons in a transparent medium?


Why can't we interpret the W, Z bosons as massive vector bosons not arising from a gauge theory?

What goes wrong if we add a mass term for gauge bosons without the Higgs mechanism?


What is our understanding of what our (i.e. observable) universe has expanded into?


What is a base unit in the new SI, and why is the ampere one of them?


Why is the speed of light in vacuum a universal constant?

If all motion is relative, how does light have a finite speed?


Why Speed of light in vacuum remains constant?

Why and how is the speed of light in vacuum constant, i.e., independent of reference frame?


In electrostatics, why the electric field inside a conductor is zero?


Deriving effective potential energy from the Lagrangian of a two-body system


When is the Hamiltonian of a system not equal to its total energy?


Is spin 1 described by $SO(3)$ or $SU(2)$

Queries about rotational groups $\mathrm{SO}(3)$ and $\mathrm{SU}(2)$ in QM


Why is the standard model renormalizable if we believe it is an effective theory?

Why should the Standard Model be renormalizable?


Given Newton's third law, why are things capable of moving?


If I could halt all motion would I stop time?

If I could stop ALL motion would I stop time?


Why we can know what flavor the neutrino is created but not their mass?


What possible advantage could there be in connecting several identical batteries in parallel?


When we ride a bicycle then we can balance it but when we apply brakes then we need to put our legs down else we may fall, why?

Why doesn't a bike/bicycle fall if going with a high speed?


Incline Plane - Coefficient of friction and kinetic friction


How come everything in the universe except the universe itself are spinning?

What if the universe is rotating as a whole?


What fundamental force is at play in electron degeneracy pressure?

Is Pauli-repulsion a "force" that is completely separate from the 4 fundamental forces?


What does the term $e^{-h\nu /kT}$ in Boltzmann distribution function mean and what roles does it play?

How can I intuitively understand the Boltzmann factor?


Why is blowing so different than sucking?

Why does blowing on a candle put it out but sucking doesn't?


Why does time in Minkowski's space have the opposite sign of the space coordinates?


Quantum Mechanics reference book similar to Classical Electrodynamics by Jackson (without QFT)

What is a good introductory book on quantum mechanics?


How does flatulence travel through the room when opening a window?

When I open a window to air out the room, how does the smell disperse?


Can a battleship float in a tiny amount of water?


What's the curve that a piece of card makes when its sides are pushed together?


Is it possible for electromagnetic waves in the Extreme Low Frequency range to carry HQ video and audio signals?

What is the equation relating maximum data transfer rates for a given EM bandwidth?


How much effect does the Bernoulli effect have on lift?


How does a liquid state in Earth's inner/outer core allow a magnetic field?


Is there any way to attract or repel neutrons?


Definition of electric charge and proper explanation


Why can't a particle that carries magnetic charge exist?

Why do physicists believe that there exist magnetic monopoles?


Is every object in the universe really expanding? Even small scale objects like humans?

Why does space expansion not expand matter?


A pendulum with an hollow bob full of flowing sand

Time period of simple pendulum with varying mass


Electrostatic shielding : charge inside a cavity


What does this depiction of a black hole in the movie Interstellar mean?


Does gravity exist in higher dimensions?

Does Coulomb's Law, with Gauss's Law, imply the existence of only three spatial dimensions?


Is there a constraint on the Lagrangian that prevents it from having multiple stationary points?

Several stationary points of the action functional


What importance of battery " voltage" between cathode and anode in photocell?

Is photocell current equal zero at threshold frequency?


What is the origin of the factor of $-1/4$ in the Maxwell Lagrangian?


Earth moves how much under my feet when I jump?


Clarification for the formulae for Differential Cross Section in Scattering theory


What experiment would disprove string theory?


What applications would room temperature super conductors have?


Black Holes without Schwartzschild Radius condition?

If a mass moves close to the speed of light, does it turn into a black hole?


Degree of freedom paradox for a rigid body


Gravity in an Earth-sized hole in "solid" outer space

Ambiguity in applying Newton's shell theorem in an infinite homogeneous universe


Why an open tube at both ends suffers resonance?

How can standing waves be produced in an open organ pipe if the ends are open?


What is the proof of constant energy in the universe?

Is the total energy of the universe zero?


How is observable universe so big if the universe is so young?

How can a quasar be 29 billion light-years away from Earth if Big Bang happened only 13.8 billion years ago?


If I run along the aisle of a bus traveling at (almost) the speed of light, can I travel faster than the speed of light?


Derivation of Maxwell's equations from field tensor lagrangian


Am I right in thinking that black holes are not infinitely dense since they grow in size?

What is exactly the density of a black hole and how can it be calculated?


How does Newton's 3rd Law apply to arm wrestling?

Given Newton's third law, why are things capable of moving?


What is exactly/literally meant by observing in Schrodinger's cat thought experiment?

What counts as "observation" in Schrödinger's Cat, and why are superpositions possible?


Why ball fall at same location from where we throw it?

The Earth is spinning, so why don't we jump and land on a different location?


Projecting double slit onto fog instead of screen

Has a double slit experiment ever been done using a track chamber or even contemplated?


Independents fields and the Lagrange Density of Schrodinger equation

Why treat complex scalar field and its complex conjugate as two different fields?


Could this experiment show how big the universe really is?

Is it possible to experimentally show that observable universe is much larger than ~93B ly?


Why singularity in a black hole, and not just "very dense"?


Shouldn't the frequency increase the current in the photoelectric effect

Photoelectric Effect - Dependence of current on frequency


Non-unitarity of finite dimensional Lorentz group and its implications


Does the LHC see electro-weak symmetry breaking?

Are there massless bosons at scales above electroweak scale?


Regarding black holes and the speed of light


What is a physically intuitive description of the "dot product" and "cross product"?

What is the physical significance of dot & cross product of vectors? Why is division not defined for vectors?


Light and laser effects on surfaces. How and why do they cause a material to decay?

Why isn't it allowed to use a flash when taking pictures in a certain place?


Why is the work done by a rocket engine greater at higher speeds?

Where does the extra kinetic energy of the rocket come from?


What are good examples to demonstrate Einstein's mass-energy relation


Same amount of calories burned for half the reps and double the weight?

How to calculate calorie expidenture from lifting a weight?


Is it possible to emit an arbitrary Spectral Color

Does there exist a laser that is tunable over the whole visible spectrum?


Why doesn't an electromagnetic wave violate conservation of energy?


Why does kinetic energy increase quadratically, not linearly, with speed?


Why do metals only glow red, yellow and white and not through the full range of the spectrum?


Triangle law of vector addition for parallel vectors


Significant figures in a practical experimental problem

Multiple measurements of the same quantity - combining uncertainties


Is $H_2O$ the only compound which has a density anomaly?


Electric field around a infinite plate with voltage $V$

Electrostatics and potential of points around charged plates


Is there a basic/elementary mass in the universe?

Why do we have an elementary charge but no elementary mass?


Will a bullet fired from a gun perpendicular to the surface of Earth return?

Could one fire a bullet with sufficient speed to leave the Earth?


How to take into account the symmetry of the metric tensor when doing the Functional derivative in GR?

Variation of the metric with respect to the metric


Understanding statistical mechanics for a non-physicist

Recommendations for statistical mechanics book


How to solve this complex Gaussian integral?

Gaussian integral with imaginary coefficients and Wick rotation


The math to come to this conclusion? If we lost all the dead space inside our atoms, we would each be able to fit into a particle of lead dust

If particles are points, then aren't atoms empty space?


What is the meaning of the size of a particle in QFT?


Weak decay iff or if strangeness changes?

Understanding type of force interaction in particle decays


How can I send a message to myself in the past?

Is time travel possible? Is it possible to go back in time?


What happens if you fly a drone inside moving passenger airplane?


If a photon has no mass why doesn't it have infinite speed?

Why can't massless particle exceed speed of light?


If photons mediate EM force? How can they tell to be attracting?


Free Body Diagram for a Body on a Smooth Inclined Plane

Question about normal force acting on a mass on an inclined plane


Why speed of light is constant with respect to any inertial frame of reference?

Why and how is the speed of light in vacuum constant, i.e., independent of reference frame?


In quantum mechanics, how exactly do we associate Hermitian operators to classical observables?

How to promote algebraic expressions to operators in quantum mechanics?


Is the Pauli exclusion principle also involved in free electrons?

Pauli exclusion principle in an electron beam


How is the Universe expanding faster than the speed of light?


What experiment confirms $\mathbf{J}^2 = \hbar^2 j(j+1)$?

Why is orbital angular momentum quantized according to $I= \hbar \sqrt{\ell(\ell+1)}$?


Quantum vacuum thruster and conservation of momentum

What are the proposed theoretical explanations for the EmDrive?


Books recommendations for my theoretical physics library


How does water evaporate if it doesn't boil?


How does the mass of black holes become so much larger than an average star


Mathematics behind particle on a ring in QM

Full solution of the quantum particle on a ring


Why is the $\frac{1}{2}$ significant in $\frac{1}{2}\rho v^2 C_d A$?

Why is the drag force proportional to $v^2$ and defined with a factor of $1/2$?


Determining if two resistors are in series or in parallel.

Detecting if resistances are parallel or series in complex circuits


Standard green glass reflection and absorption rates by wavelength

Why does a glass window reflect white objects white from an atomic scatterers’ viewpoint?


Why there cannot be source-free spherical symmetrical EM disturbances?

Why does a monopole not radiate energy in electodynamics?


Sign mistake calculating electrostatic potential energy formula!

Electric Potential produced by Hollow Sphere


Textbook on Differential Geometry for General Relativity

Mathematically-oriented Treatment of General Relativity


Why can we see the moon when it is between the Earth and the Sun?

How can we see the moon while it's between the Earth and the Sun?


Lorentz invariance of Dirac equation if $\gamma^\mu$-matrices were numbers


Could a man float in a large enough magnetic field to simulate zero gravity?

How strong of magnetic field would noticibly attract a person?


Taking Honor Mechanics class in college this semester and It would be great to get your opinions on advanced textbooks compatible with such a class?


Undefined Hamiltonian for this particular Lagrangian

How to find Hamiltonian from this simple Lagrangian? (tricky)


If temperature is related to average kinetic energy in an ideal gas, then does speeding up the gas container affect its temperature?


Why frequency does not change when light passes through the denser medium?

What determines color -- wavelength or frequency?


Why do quarks have the masses that they do? And why is the 'down' (negative) quark heavier than the 'up' (positively-charged) one?

Why is the up quark is lighter than the down quark, while top is heavier than bottom?


Are there accepted spectral lines, or wavelength of light emitted, for the various neural and ionized atoms? If yes, where can I find them?

What are good, reliable databases of atomic spectra?


How to reintroduce $\hbar$ and $c$ into a formula written in natural units?

How to find the corrsponding expression after working with natural units $\hbar=c=1$?


Do irreversible processes indicate that time reversible symmetry is a limited phenomenon instead of a universal law?

Does the scientific community consider the Loschmidt paradox resolved? If so what is the resolution?


What makes north pole of a magnet north pole in the first place?

What's the difference between the north and the south pole on a magnet?


Since two particles can be paired can we use them for instant communication?


Why would spacetime curvature cause gravity?


Resistance to electric current in conductors


Would it help if you jump inside a free falling elevator?


How small does a hole in a cup have to be to hold water without dripping?

How to find out the maximum radius of a hole that can keep water stay in a container by water viscosity?


How do I understand Kinetic energy formula?

Why does kinetic energy increase quadratically, not linearly, with speed?


How can a proton be converted to a neutron via positron emission and yet gain mass?


Is time travel possible? Is it possible to go back in time?


Is it possible to use "negative sound waves" to "cancel out" a sound to create silence?


What's the physical significance of the off-diagonal element in the matrix of moment of inertia


Why are springs shaped the way they are?


Why we expect a black hole to have an emissivity of 1?


If universe is expanding then relative to what?


Throwing a ball from the surface of the earth so that it ends up in a circular orbit


What will happen if I will beam a ray of light in dark vaccum?


Can entropy ever decrease in an isolated system?

Is a spontaneous decrease in entropy *impossible* or just extremely unlikely?


Change in Hamiltonian under infinitesimal canonical transformation

Why is the change in Hamiltonian for an active infinitesimal canonical transformation defined the way it is?


How to explain interference of light by Huygens' principle?

How does Huygens Principle explain interference?


How does one correctly interpret the behavior of the heat capacity of a charged black hole?


Why hyperbolic shapes of colour distortion in this image?

Why do I see a saddle in this picture of a computer screen?


Rubber band stretched produces heat and when released absorbs heat.. Why?


Why isn't the Doppler effect (for sound waves) symmetric with respect to source and receiver?

Is the Doppler effect for sound symmetrical for observer or source movement?


Is there a way to detect the collapse in wave function of entangled particles instantaneously?


Theoretical/classical mechanics reference book


Schwarzschild metric in expanding Universe


Recommendations for good Newtonian mechanics and kinematics books


How does one get supergravity from string theory?

Steps for going from Polyakov action to low-energy effective action (SUGRA?) in String Theory


How do slanted indices work in special relativity?

Difference between slanted indices on a tensor


Dimensionality of a Hilbert Space: Countable or Uncountable?


Is Carnot cycle the only "most efficient" cycle?


Why do we use Root Mean Square (RMS) values when talking about AC voltage


Annihilation cross-section of neutrino-antineutrino pairs


What would happen if an object could fall straight through the Earth?

If it was possible to dig a hole that went from one side of the Earth to the other...


Current - magnetic field intensity relation


How should be the course of learning for Particle Physics?


Variation of classical action due to variation of position and time

Variation of Action with time coordinate variations


Why don't we percieve chords like we perceive the mix of two light waves?

Why can we distinguish different pitches in a chord but not different hues of light?


Is the inter-atomic spacing of a conductive material directly proportional to its resistivity?

Relationship between electrical resistivity and density


Reflection of sound waves from the open end of an organ pipe & relationship b/w nodes & pressure


Why do the big nuts always remain at top? The Brazil-nut Effect


Are density states more fundamental than wavefunctions?

Is the density operator a mathematical convenience or a 'fundamental' aspect of quantum mechanics?


Why doesn't Kirchhoff's Law work when a battery is shorted with an ideal wire?


How does a cilinder that rolls without slipping lose energy?

Consider a horizontal surface with or without friction. Ideally, will a wheel rolling without slipping roll forever in both cases?


Which book should I follow to get basic understanding of Black Holes?


Can a single atom in vacuum space have a temperature?

Can a single molecule have a temperature?


What factors influence the spring constant?


What is the theoretical limit for farthest we can see back in time and distance?


Can the Euler-Lagrange equation be used to derive the stationary action formula?

How do I show that there exists variational/action principle for a given classical system?


What if we didn't know if particle is observed in double-slit experiment?

Hidden observers in Double Slit experiments - Do they matter?


Negative electrostatic potential energy interpretation

Sign of Work and potential energy in electrostatics


What happens if particle is measured outside finite well?

Can a particle be physically observed inside a quantum barrier?


Does Big Bang predict the size of the fluctuations in the CMB?

What evidence do we have that CMB is the result of the Big bang?


What is the theory concerning gravitational atoms?

Quantum mechanical gravitational bound states


Why can't we define fundamental unit of mass?

Why do we still not have an exact (constants-based) definition for a kilogram?


How do we know that $F = ma$, not $F = k \cdot ma$


If everything travels through spacetime at c, then what about gravitational time dilation?

Four-velocity in General-relativistic geodesic equation


If refraction slows down light, isn't it possible to hold light still?


Only sea water appears blue in color, why this is not happening in river water?


An object near the speed of light can become a black hole at high speeds?

If a mass moves close to the speed of light, does it turn into a black hole?


What causes this corkscrew-shaped object to rise up in a stream of water falling down?


Why free-fall acceleration is considered constant rather than increasing?

Near Earth vs Newtonian gravitational potential


What are Tom Banks's arguments against a QFT of QG cont..?

What are Tom Banks's arguments against a QFT of quantum gravity?


In a very small static universe with only a particle, does it make sense to talk about time?


Show that normable eigenstates are not degenerated in 1D


Do COBE, WMAP, or Planck data show time-variance of the CMB's anisotropies?

How fast is the Cosmic Microwave Background Radiation (CMBR) changing?


How can a neutron star radiate when it is neutral?


Inferring the conservation of angular momentum from linear momentum

Is linear monemtum conserved with in angular momentum?


Why does Wikipedia state that angular velocity is equal to angular frequency?

Is angular frequency the same as angular velocity or are they different?


Why do wavefunctions for stationary states include $e^{-iEt/\hbar}$?

Can we safely assume $\Psi(x,t) = \psi(x)e^{-i\omega t}$ always in QM?


What's the nicest proof that two isolates masses orbit their center of mass?

Are planets actually moving in elliptical orbits around the Sun or do they move in circular orbits around their center of mass?


Phase in time evolution operator for time-dependent Hamiltonian

The formal solution of the time-dependent Schrödinger equation


Are sounds louder at night, in the winter?

Why do I always hear remote train horn at night?


Best text books for reference (dynamic-electromagnetic systems)?

Recommended books for advanced undergraduate electrodynamics


How does a knife cut things at the atomic level?


Using entanglement for communication based on the double slit experiment

EPR-type experiments and faster-than-light communication using interference effects as signaling mechanism


Maximum number of bits in one single qubit?


How can we move an object with zero velocity?


Error propagation with asymmetric uncertainties


How are string vibration modes related to particle identity?


Why can’t light induce a current while microwaves can?

Does light induce an electric current in a conductor?


Why protons and electrons attract each other?

What's the relation between virtual photons and electromagnetic potentials?


The relation between the spring constant and its radius

What factors influence the spring constant?


Can two electron moving in opposite direction move faster than light?

If I run along the aisle of a bus traveling at (almost) the speed of light, can I travel faster than the speed of light?


Why do objects rebound after hitting the ground?

Why don't all objects bounce like rubber balls?


What is behind the definitions of work and energy?


Why speed is defined as distance over time


Bernoulli's equation and reference frames


Vertically move in a helicopter to go somewhere on Earth

Why does the atmosphere rotate along with the earth?


pattern of moving electrons in wire under AC


Existence of Electric field around a current carrying conductor?

Can a magnetic field be induced without an electric field?


Which fundamental force acts while pushing a book on the table?

What does it mean for two objects to "touch"?


How do we know that $F = ma$, not $F = k \cdot ma$


Why can we pick the divergence of the vector potential?

Do we fix divergence of the vector potential $A$, because $\nabla \cdot \nabla \psi \ne 0$?


From where electrons flow to make a bulb light?


Is it possible that galaxies' redshift is caused by something else than the expansion of space?


Manifestly Lorentz invariant nature of the equation $\phi(x)=\int\frac{d^3k}{(2\pi)^3\sqrt{2\omega_k}}(a_k e^{-ikx}+a^{\dagger}_ke^{ikx})$


What is the cleverest way to calculate $[\hat{a}^{M},\hat{a}^{\dagger N}]$ when $[\hat{a},\hat{a}^{\dagger}]=1$?


Closed Loops inside a Circuit and Kirchhoff's Laws

Determining current in a branch having no resistor


Why is the time coordinate different in the metric?

Why does time in Minkowski's space have the opposite sign of the space coordinates?


After I pour a cup of tea, I can't drink it for 10 minutes. Will it stay warmer if I add the milk at the start, at the end or does it not matter?

Would a Cup of Tea Be Hotter If you Add the Milk Before or After Boiling Water?


Why in spontaneous symmetry breaking do we only look at the scalar fields?

Why cannot fermions have non-zero vacuum expectation value?


Archimedes Principle in case of Two Fluids

Archimedes' principle for two liquid layers


Does vapor latent heat depend on temperature?

What is the effect of an increase in pressure on latent heat of vaporization?


What do we know about black hole and its existence?


How can objects with no net acceleration gain energy?

When you lift a box from the floor, the potential energy changes but kinetic energy does not change. Does it violate conservation of energy?


Even though the field becomes infinite near the charge a gaussian surface can pass through the continuous charge distribution. How?

Why is flux through a closed surface not infinite?


How does our Moon stay in orbit around Earth? A question about gravitational field strength

Why does the Moon not revolve around the Sun directly?


Why doesn't nuetron-neutron bound state exist?

Why are the dineutron and diproton unbound?


If photons have no mass, how can they have momentum?


Angular momentum conservation in a non-inertial frame

When conserving angular momentum, about which point(s) should it be calculated?


Is there any proof particles really exist?

Do photons truly exist in a physical sense or are they just a useful concept like $i = \sqrt{-1}$?


Huygen's principle: how does wavelet formation work?


Fermi's golden rule and infinite probablity?


Is the universe expanding or is it simply the matter within it spreading out further?


Geometrical description of canonical commutation relation

Geometric description of canonical commutation relation


If gravity is a gauge theory, what is the Lie group?

argument about fallacy of diff(M) being a gauge group for general relativity


How does an isolated electron in deep space 'know' it is spinning?

What is spin as it relates to subatomic particles?


Moving from acceleration- gravity equivalence to general relativity


What is meant by the temperature of an atom?

Can a single molecule have a temperature?


How can we prove charge invariance under Lorentz Transformation?


What is the origin of the electric charge?


How does current flow in a short circuit?

Why does all the current flow through a short circuit if its voltage drop is considered zero?


What is the time derivative $\frac{d}{dt}(\exp(\hat A))$ of operator exponential $\exp(\hat{A})$?

Derivative of the product of operators and Derivative of exponential


Why is work defined with respect to distance rather than time?

Why does the amount of energy transferred depend on distance rather than time?


Quantum numbers $n$ and $\ell$ relation in many electrons atom

Why do non-hydrogen atomic orbitals have the same degeneracy structure as hydrogen orbitals?


Why does the frequency of a wave does not change on reflection and on transmission?

Why doesn't the frequency of light change during refraction?


Surface tension: the paper clip experiment


Orthonormality: from finite ($\delta_{ij}$) to infinite ($\delta(x-y)$) dimensional vector spaces

How is the "normalisation" of non-normalizable states chosen?


How could someone calculate the coulomb barrier transparency in 3 dimensions

With what probability does nuclear fusion occur at energies far below the Coulomb barrier?


Why is neutron slightly heavier than the proton?

What's with the very slightly larger mass of the neutron compared to the proton?


How does Fermat's principle of least time come from this statement?

How is Fermat's least time principle proven?


Which is more important for a force of the impact mass or velocity?


Quantum gravity: How do we know gravity operates at quantum scales?

What are the reasons to expect that gravity should be quantized?


Intuition behind the use of the Principle of Stationary Action in Classical Field Theory


Why don't electrons crash into the nuclei they "orbit"?


When atom absorb energy, how does the nucleon know?

How does one account for the momentum of an absorbed photon?


How to calculate Hamiltonian when Lagrangian has higher order derivatives?

How to obtain Hamiltonian formalism and phase space for Lagrangian with second-derivatives?


Why does the sun always have some whiteness?

Why does bright pure red/green/blue light look white if bright enough?


Why are so many forces explainable using inverse squares when space is three dimensional?


The Special Relativity springs from the space-time nature?

What is the proper way to explain the twin paradox?


Calculating adjoint representation of Lie group/algebra

Solving the Lie algebra of generators: path from algebra to matrix representation


Relation between spin and polarization of photon?

Difference between spin and polarization of a photon


Why does a free-falling body experience no force despite accelerating?


How can the action can describe a movement? What is the argument behind?

Is there a proof from the first principle that the Lagrangian L = T - V?


What is the force between two charged objects when the space between them is partially filled by a dielectric medium?


Should two laser pointers always shine a point on the screen with same intensity?


What is the significance of the de Broglie wavelength?

Is the wave-particle duality a real duality?


If a mass moves close to the speed of light, does it turn into a black hole?


What happens when a charged capacitor is connected to an uncharged capacitor

Why does a floating capacitor act differently than a grounded capacitor?


Books for particle physics and the Standard Model


Does writing a file to a solid state drive change the mass?

Is a hard drive heavier when it is full?


Why Andromeda is approaching the Milky Way in an expanding universe?

How and why will the Milky Way collide with the Andromeda galaxy?


How is acceleration calculated when only the direction of velocity changes and the magnitude remains the same?

How is acceleration measured if there is change only in the direction of velocity & not magnitude?


Could a human, even in principle, hear a gravitational wave? If so, how powerful must it be?

Would you hear a gravitational wave, if its amplitude and frequency were suitable?


How does a rocket travel in a vacuum space?

What is a rocket engine thrusting against in space?


What would happen to the Sun if you reflect all its emitted e.m. radiation back?

What would happen to a star if a Dyson sphere lined with mirrors reflected a significant portion of the stars light back to the star


Why do electrons flow in the opposite direction to current?

Why is the charge naming convention wrong?


Fields that lend themselves to variational principles?

How do I show that there exists variational/action principle for a given classical system?


What exactly is a frame of reference in Newtonian mechanics?

A concise definition of a frame of reference in Newtonian mechanics?


Does a magnetic field (moving relative to the charge) act on a stationary charge?

Force of moving magnetic field on stationary charge


What is meant by the stationary states in quantum mechanics?


Can third-order phase transitions be understood from a symmetry-breaking viewpoint?

Third-order phase transition in Landau theory


Unifying quantum mechanics and general relativity

A list of inconveniences between quantum mechanics and (general) relativity?


Why does the term $-\frac{q}{c}\frac{d\vec{A}}{dt}$ play no part in the Lagrangian of a charged particle in an electromagnetic field?

Derivation of Lagrangian of electromagnetic field from Lorentz force


How can friction do no work in case of pure rolling?


How can a singularity in a black hole rotate if it's just a point?


Good book on the standard model for theoretical mathematicians

Books for particle physics and the Standard Model


Relativistic time dilation on Mars compared to Earth?


Why does the clock work slowly at higher speed?


About my last question of the problem of young experiment

What's the problem with my Young slits experiment?


A point on a disc travelling at the speed of light

Euclidean geometry in non-inertial frame


When to use $x = A \sin (wt + p)$ and $x = A \cos (wt+p)$ during Simple Harmonic motion when we start our clock not between mean and extreme position?

Using $\sin()$ or $\cos()$ for computing SHM?


Why does space expansion not expand matter?


Recommended books for advanced undergraduate electrodynamics


What are matter waves made of and what is their speed?


What happens to the rest of the 95 percent in quarks?

Quarks in a hadron: where does the mass come from?


Why is gravity called the weakest force?

What does it mean to say "Gravity is the weakest of the forces"?


What is the relation between electromagnetic wave and photon?


How to tell the difference between redshift by motion of stellar objects and the expansion of space?

Do cosmological and Doppler redshift produce different patterns?


Can we have chaotic motion due to the finite precision of our calculations?

Why is the computer useful if a chaotic system is sensitive to numeric error?


In general relativity, if an object has no speed is it then not affected by gravity?

What makes matter travel along geodesics?


Velocity of different sized balls rolling down the same rail

How does separation of tracks affect the acceleration of a rolling ball on the tracks?


Solving the 2nd order linear differential equation in $LC$ oscillator

Need help understanding an equation of motion for a pendulum


Evidence that Time is a Natural Phenomenon?

What is time, does it flow, and if so what defines its direction?


What happens when a photon hits a mirror?


How local gauge invariance explain charge conservation and electromagnetic force appearance?

What, in simplest terms, is gauge invariance?


Meaning of the terms in Wave Equation for a Transverse Wave


Why a fan make us feel colder instead of warmer in a cold room?


Einbein in action for relativistic particles

What is the reasoning that leads one to postulate this second form for the relativistic particle action?


Why was a third particle, the neutrino, necessary to explain the continuous energy spectrum of beta-decay?

Why is the spectrum of the $\beta$-decay continuous?


Show that a particle of spin 1 cannot decay into two identical particles of spin 0 - a Seond Go

Why can't a spin-1 particle decay into two identical spin-0 particles?


Does the eigenvectors of Hermitian operator constitute a basis

Do eigenvectors of quantum operators span the whole Hilbert Space?


Why does $(\frac{1}{2}, \frac{1}{2})$ representation of $SO(1,3)$ Lorentz group act on $2\times2$ Hermitian matrices?

Why is the $(\frac{1}{2},\frac{1}{2})$ representation of the Lorentz group realized as the vector space of Hermitian $2\times 2$ matrices?


Is there a reason behind why Archimedes principle works?

What is the basic reason behind buoyancy?


How to calculate average velocity using a series of measurements?

What is the difference between these two ways to calculate average velocity?


What is the relation between electromagnetic wave and photon?


Trying to understand the difference between $\Delta t$ and $dt$

Difference between $\Delta$, $d$ and $\delta$


Does the Planck scale imply that spacetime is discrete?


What would happen if the wavelength of light gets doubled?

How can wifi penetrate through walls when visible light can't?


How to explain curvature of spacetime at the time of big bang

If the universe is expanding, what is it expanding into?


Rope with no slack tied around the world

Is it possible for information to be transmitted faster than light by using a rigid pole?


How can a neutron star have a magnetic field when its particles are neutral?

How can a neutron star radiate when it is neutral?


In electromagnetism, why does nature prefer the right-hand rule over the left-hand rule?


Show bigger amplitude of physical pendulum means bigger period


If I move an object with my hand, will the object's temperature increase?

How does temperature relate to the kinetic energy of molecules?


What are good books for special relativity?


Weight of a container of gas and container shape


Treating a differential as a difference of two quantities---legal or no?

How to treat differentials and infinitesimals?


Energy conservation and quantum measurement


Will everything eventually be a single black hole?

Is it possible that black holes might devour all masses of the universe?


Colour Temperature and the thermal temperature

If blackbody radiation at 6000K peaks in the optical, why aren't fluorescent bulbs at 6000K?


Could enough people spin Earth backwards faster than they could run?

Do mankind and manmade activities/constructions have any effect on the rotation of the Earth?


Superposition of distinct vevs in spontaneous symmetry breaking


Why does the road look like it's wet on hot days?


Would there be centrifugal force if I were alone in the universe?


Why does a bird not get electrocuted when it is sitting on a high tension electric wire?

Why do birds sitting on electric wires not get shocked?


Time Evolution of a Maximally Entangled State

Unitarily evolving a separable state into an entangled one


Why mass of nucleus decreases after binding of it's components (protons and neutrons)?

Mass defect- From where mass is being lost?


Question regarding electrostatic potential energy

What is the energy of a single charge system?


If I run along the aisle of a bus traveling at (almost) the speed of light, can I travel faster than the speed of light?


Using complex exponential to represent waves in EM

What is the physical significance of the imaginary part when plane waves are represented as $e^{i(kx-\omega t)}$?


General question about dimensionality of the universe

Universe being flat and why we can't see or access the space "behind" our universe plane?


How is the mass of an electron distributed?


Difference between sound and high temperature

How loud is the thermal motion of air molecules?


Why is $x^n \psi^{(m)}(x)$ zero at infinity?

Normalizable wavefunction that does not vanish at infinity


Wouldn't gravitons themselves theoretically be affected by gravity?


Why Bohr atom model is still being tought in high school?

Where are the inaccuracies in the Bohr model of the atom?


Intuition behind creation and annihilation operators?

Consistent, complete, and generalized description of the quantum harmonic oscillator


What will happen if a stick and a beam of light is to race

Is it possible for information to be transmitted faster than light by using a rigid pole?


how to derive schrodinger equation from heisenberg equation?

How to derive the Schrödinger Equation from Heisenberg's matrix mechanics and vice-versa?


Where do the bipolar jets of black holes come from?


What is the relation between terminal potential difference and e.m.f?

What is the difference between EMF of a battery, its potential difference and the current supplied by the battery?


Quantum eraser: How does photon detection in an interference pattern "dark spot" not affect the state of the remaining photon?

Can post-selecting on the screen in the Delayed Choice Quantum Eraser experiment be used to predict the quantum-eraser measurement results?


What are some good books for classical mechanics of continuous systems?

Modern references for continuum mechanics


Can a photon transmit a momentum to a neutron?

Has a free neutron ever been shown to absorb/emit/interact with a photon?


Why taking components of a component of a vector is invalid?


Why isn't Hawking radiation of negative energy?

Black holes and positive/negative-energy particles


Gravitational lensing in the form of optical equation $\frac{1}{p} + \frac{1}{q} = \frac{1}{f}$?

Do gravitational lenses have a focus point?


Why use $SU(3)$ and not $SL(3, \mathbb{R})$ for color charge?

Why is the Yang-Mills gauge group assumed compact and semi-simple?


Are gravitational force and gravitational time dilation proportional?


Why does an aluminum foil spark inside a microwave oven?

Why do metal objects in microwaves spark?


In quantum mechanics, is energy conservative statistically or for every single system?

Conservation of energy and wavefunctions


How exactly is white light a combination of several wavelengths?


Will a can filled with vacuum move when we let in air?

What happens, if a rocket is filled with a vacuum instead of high pressured air?


Has the universe we live in started as a black hole that is imploding?


Why do photon only interact with atoms whose electronic orbitals are at very particular energies?

How do photons know they can or can't excite electrons in atoms?


Why do sunbeams diverge even though the sun is much more than a few kilometers away?


What is the "explosion" caused by Hawking radiation, and how do you calculate its strength?


Will the capacitance of a parallel plate capacitor be different if the overall charge on it is not neutral?

Capacitor with different charges on each plate


Can we falsify photons having a tiny mass, experiencing subjective time, and traveling slightly slower than $c$ (like neutrinos)?

Is it experimentally proven that photons travel at speed $c$ in vacuum?


Which quantities are Lorentz-Invariable and which are not?


Why time is attached with space and how apple fall according to Einstein?

How does "curved space" explain gravitational attraction?


How can wind feel colder than normal air if it has more energy?

Why does a breeze of wind make us feel cooler?


Noise cancelling speakers to cancel sound in the room

Is it possible to use "negative sound waves" to "cancel out" a sound to create silence?


Destructive interference and energy conservation


Where does the energy when a photon hits an electron but the electron doesn't doesn't gain enough energy to change level?

photon electron interaction such that the photon energy does not correspond to any state change


Is it possible for a massless particle to have a charge?


Why is the definition $\text{Work}= \text{Force}\cdot\text{Displacement}$ useful to describe the physical world?


Will an entangled system give different measurement then just correlation?

Correlation vs. entanglement for composite quantum system


Why is $\langle x|x'\rangle=\delta(x-x')?$

Why is $\langle x| x' \rangle=\delta(x-x')$?


Why don't cell phones pick up music in phone calls?

Why can't you hear music well over a telephone line?


In a Skew Cylinder does pressure at the bottom face depend on depth or mass of Fluid

Dependence of fluid pressure being on height and not mass


Phase shift of 180 degrees of transversal wave on reflection from denser medium


Does special relativity imply that time dilation is affected by an orientation of clocks?


What's the proper distance from the event horizon to the singularity?

How much extra distance to an event horizon?


What would happen if a black hole swallowed a white hole?

Collision of a black hole & a white hole


Rotating Cone - Finding Energy and Momentum


Performing Legendre transformation when conjugate momentum is independent of time derivative of generalised co-ordinates


What is the reason to believe that the laws of physics are same in all frames of reference?

How do we know that the laws of physics are invariant in all inertial frames?


Oppossing Laser Beams Cause One Beam to Disappear

Opposing Laser Beams Turns One Laser Off


Is there gravitational black hole radiation?

How many of which particles are in Hawking radiation?


How can a black hole grow, as seen by an outside observer?

How can anything ever fall into a black hole as seen from an outside observer?


Is there a rotational analog for Newton's laws of motion?

Is there a rotational equivalent to newtons laws?


Biot - Savart Law and time - variable current

Is Biot-Savart Law valid for time-varying currents unlike Ampere's law?


Why bodies with different masses reach gound at the same time in vacuum?

Why do two bodies of different masses fall at the same rate (in the absence of air resistance)?


Does energy exist, or is it just a relationship between other fundamental things?


Intuition of Distance covered when accelerating

Why there is a $\frac{1}{2}$ in the distance formula $d=\frac{1}{2}at^2$?


Are black holes bound to merge once their event horizons touch?

Is there a geometric reason why two merging black holes never “decay” into two separate black holes


How do you calculate how heavy you feel from negative g forces?

How much weight do you feel during negative g-forces?


Contradictions in electric field of infinite uniform charge distribution

Gauss's law in a uniform charge distribution extending infinitely in all directions


How to beat speed of light using graphene pulley motor?

Rotate a long bar in space and get close to (or even beyond) the speed of light $c$


In a circuit, do surface charges get influenced by external electric fields?


Sun’s corona is so much hotter than Chromosphere

How does the sun's surface conduct thermal energy from the convective zone to the corona?


How are quarks elementary when they can become leptons?

Is the Higgs boson an elementary particle? If so, why does it decay?


Proof of the superposition theorem in linear circuit analysis

Is there a formal proof for the superposition theorem?


How can changing magnetic field produce instantaneously the electric field and vice versa?

Why do electromagnetic waves have the magnetic and electric field intensities in the same phase?


Lagrangian, central forces and conservation of angular momentum


How is angular momentum conserved for the orbiting body if the centripetal force disappears?

How is Angular Momentum Conserved when Mass is Released?


Why don't electrons crash into the nuclei they "orbit"?


What are "on-shell" and "off-shell" conditions in classical mechanics?


How will a particle with energy less than $V_{\rm min}$ behave?


Electrodynamics textbooks that emphasize applications


Naive question - Is Magnetic generator (like this) not a 'perpetual motion machine'?


Is the value for the speed of light in vacuum irrelevant?

Why do universal constants have the values they do?


Is possible to create black hole in laboratory?

Can black holes be created on a miniature scale?


Why does heisenberg uncertainty principle work?

Isn't the uncertainty principle just non-fundamental limitations in our current technology that could be removed in a more advanced civilization?


Reference Request: Physics 1 for people who already know the math

Which Mechanics book is the best for beginner in math major?


Conservation of energy when external force is applied

Is conservation of energy only for isolated systems?


Wave equation: $y=A \sin(\omega t-kx)$ or $y=A\sin(kx-\omega t)$?


Does light get acceleration due to gravity?


How can neutral atoms have exactly zero electric field when there is a difference in the positions of the charges?

Is there an electric field around neutral atoms?


What is the formal definition of Degree of Freedom?


If gravity isn't a force, then why do we learn in school that it is?


How does a photon experience space and time?


Scientific reason behind electromagnetic induction

Is there is any way to prove the Faraday's law of induction?


How do we get a expression for speed of light $\frac{1}{\sqrt{\mu\epsilon}}$ using Maxwell's equation?

Derivation of the speed of light using the integral forms of Maxwell's Equations


What is degree of freedom in thermodynamics?


Should we need to consider time dilation effect when travel in a very fast rocket?

How long would it take me to travel to a distant star?


Given Newton's third law, why are things capable of moving?


Why does Hawking radiation outside the Schwarzschild radius decrease a black hole's mass?

Black holes and positive/negative-energy particles


What is the physical meaning of divergence?


What is the reason for the emission of electromagnetic waves from the sun?


Is physical entropy opposite to information entropy?

Is information entropy the same as thermodynamic entropy?


What determines the size of a straw/pipe to stop a liquid running out of it when closing one end of it?


Potential Energy equation is wrong as $mg$ force acting upwards (by us) and gravitational force ($-mg$) get cancelled and no movement is possible

How can we move an object with zero velocity?


Why the extra term $\frac{1}{2}(\partial_{\rho}A^{\rho})^2$ in the photon Lagrangian?


If the particles show uncertainity ,then why the body made of particles cant show that?

Validity of naively computing the de Broglie wavelength of a macroscopic object


Equivalence Principle: from falling bodies to all physical processes

How did Einstein generalise the Einstein elevator thought experiment to conclude with the equivalence principle?


Which phenomenon is related to the spin of photons?


Is there a mass spectrometer software that can measure the mass of a hydrogen atom

Is there a mass spectrometer software that can measure the mass of a proton


Noether's conserved charges: why are there not "spatially" conserved charges?

Does Noether's theorem also give rise to quantities conserved over space?


What is Lie-dragging? What is the relationship between Lie-dragging and Lie-derivative?

What is the physical meaning of Lie dragging?


A physical explanation for negative kelvin temperatures


Is the answer to the question "How many moments in time exist between any two particular moments?", infinitely many?


What happens if I add a single quark to a system of hadrons?


Why does a ball rolling without slipping stop due to friction?

Will a pure rolling cylinder stop on a rough surface?


Why does a magnetic field "curl" around a current carrying element?

Why do magnetic field field lines behave the way they do?


Does a black hole evaporate by the time an observer reaches the singularity?

Does any particle ever reach any singularity inside the black hole?


Momentum is conserved in the gravity of general relativity?

General relativity and the conservation of momentum


Why is $\mathfrak{so}(3,1)_{\mathbb{C}}^\uparrow \cong \mathfrak{su}_\mathbb{C}(2) \oplus \mathfrak{su}_\mathbb{C}(2)$

How do I construct the $SU(2)$ representation of the Lorentz Group using $SU(2)\times SU(2)\sim SO(3,1)$ ?


Why can't a pyramid stay balanced on a vertex?

Can we theoretically balance a perfectly symmetrical pencil on its one-atom tip?


What is the physical significance of electric flux?


What is the educational path to properly understanding the Higgs Boson?

What is a complete book for introductory quantum field theory?


Are there other formalisms apart from Newtonian, Lagrangian and Hamiltonian?

Are there other less famous yet accepted formalisms of Classical Mechanics?


Why do I always hear remote train horn at night?


Effect of humidity on removing excess charge from objects


Tension of a string on a rotating sphere and under the influence of gravity

Is an explanation of 'effect of Earth's rotation on $g$' possible from an inertial reference frame?


Why does gravity becomes negative when finding the negative derivative of potential? (I know $F=-dU/dx$) Why is $F$ itself negative?

Why is the potential energy equal to the negative integral of a force?


Is it possible to see the Milky Way galaxy through a gravitational lens?

Since there are gravitational lenses, are there gravitational mirrors?


How is distance between galaxies and rate of expansion of universe calculated?

How does the Hubble parameter change with the age of the universe?


Why do harmonics occur when you pluck a string?


If I jump, would I be displaced from my initial position since the Earth is moving?

Earth moves how much under my feet when I jump?


If Time and Space are intrinsically linked and space is ever expanding then surely time is slowing down

Does time expand with space? (or contract)


The gauge of a wire vs electrical resistance

Dependent and Independent Variables in an Electrical Experiment


How understand the stored energy due to magnetic field?

What is the mechanism by which magnetic fields do work?


What is physical meaning of an operator to applied on a wavefunction?


Analogue of $\varepsilon_0$ for gravitational mass?

Newton's Law of Graviation: Why $G$ and not e.g. $\dfrac{1}{4\pi G_0}$?


How do we know the maximum speed of conventional matter is the same as the speed of light?

What is so special about speed of light in vacuum?


The Euler-Lagrange equations for rigid body rotation


What is the physical significance of dot & cross product of vectors? Why is division not defined for vectors?


What is the reason behind water not falling from a bucket at the top of loop?


Will we ever stop receiving CMB photons on earth?


What is the physical intuition for Bloch Sphere?


Relating torque and time rate of change of angular moment when an object isn't rotating about its center of mass

How to find Origin for Angular Momentum?


Electric field inside a conductor under influence of non uniform electric field

Why is the field inside a conducting shell zero when only external charges are present?


Can a system have a negative energy? What is the energy of black hole compared to the normal star?

Is it possible for a system to have negative potential energy?


Maximum Electron Speed Around an Atomic Nucleus

Is this a correct demonstration for why elements above untriseptium cannot exist?


Books for Group theory in particle physics


What happens if I increase the magnitude of the centripetal force?

What if the net force provided for a circular motion is larger than the required centripetal force?


For regular moving objects around us, how many times can I differentiate their position with respect to time until I reach a constant?

When motion begins, do objects go through an infinite number of position derivatives?


Electric field and potential in a point inside conductor for a particular case

Is electric field inside a cavity necessarily zero?


Can a stable structure actually enclose a black hole of a certain radius?

Could a Dyson Sphere-like object be made to encase a black hole without collapsing?


Why is not both sides of a fan equally effective?

What is going on in front of and behind a fan?


Consequences of Einstein's Equivalence Principle


Why is a $3d$ orbital in transition metal higher in energy than a $4s$ orbital?

How are Quantum Mechanical energy levels related to atom shells?


In simple terms, is the permittivity of free space the polarizability of a vacuum?

Why does the vacuum even have permeability and permittivity?


Calculating the magnitude of magnetic field created by magnets

Can we calculate the magnetic field of a permanent magnet?


If mass is homogeneously distributed why would there be gravitational attraction between bodies?

Why isn't an infinite, flat, nonexpanding universe filled with a uniform matter distribution a solution to Einstein's equation?


Why is Gibbs Free Energy not equal to 0? Its definition itself makes it 0


Do superconductors really have 0 resistance in reality?

If a superconductor has zero resistance, does it have infinite amperage?


How to find the unitary operation of a depolarizing channel?

Explicit construction for unitary extensions of completely positive and trace preserving (CPTP) maps?


If the velocity of an object is zero, does it mean that the acceleration is zero?

How can an object's instantaneous speed be zero and it's instantaneous acceleration be nonzero?


Confused about inductors and how they "react to changes in current"

How does current flow if back emf equals to applied voltage


According to the state postulate ,the state of a simple compressible system can be completely specified by 2 independent intensive properties

Why is the state of a simple compressible system completely specified by two independent intensive properties?


Special relativity: Two moving objects from different reference frames


Why don't elementary particles with spin $\frac{3}{2}$ exist?

What are the mathematical problems in introducing Spin 3/2 fermions?


Nothing can exceed the speed of light but what if we accelerate a particle that contain electron that have a speed near to speed of light?

If I run along the aisle of a bus traveling at (almost) the speed of light, can I travel faster than the speed of light?


Why isn't the product rule used in the definition of mechanical work?


What is the relationship between binding energy, energy released, and mass defect?


Is space and time consecutive in physics, like frames in cameras?


How can we determine if an equation represents a travelling wave?

Why should a solution to the wave equation be finite?


What is thermal radiation on a molecular level?

What are the various physical mechanisms for energy transfer to the photon during blackbody emission?


Isospin conservation for total isospin or third component of isospin?


Deriving conserved charges from the equations of motion

Elementary argument for conservation laws from symmetries *without* using the Lagrangian formalism


What does spacetime interval really mean?

What do spacelike, timelike and lightlike spacetime interval really mean?


Problem understanding Many-Worlds Theory

How does many worlds interpretation work for non-50/50 probabilities?


How can an observer reach the singularity if black hole interiors grow forever?

How can anything ever fall into a black hole as seen from an outside observer?


How do electrons move from one energy level to another?

Do electrons really perform instantaneous quantum leaps?


If time is the 4th dimension, which is more accutate?

What is time, does it flow, and if so what defines its direction?


Does Special Relativity Predict Absurdities?


Why Ampere's law uses the current which passes through the open surface only?

Integral version of Ampere's law: why current outside the surface does not contribute to $\oint B\cdot d\ell$?


Why is a black hole referred to as massive?


Lie bracket for Lie algebra of $SO(n,m)$


Why is the equation of state only a function of three variables?


Would birds be able to fly if the air had no viscosity?

Does a wing in a potential flow have lift?


Why do we treat the action as dimensionless in QFT?

Why is the action dimensionless in natural units?


Can someone explain me the origin of the sound from this YouTube video (link given)?


Instead of space expanding maybe atoms are shrinking?

How do we know the universe is expanding, and not that its contents are shrinking?


If gravity is simply a curvature of space, why does it accelerate objects?

How exactly does curved space-time describe the force of gravity?


D'Alembers Principle - further explanation

Why is the d'Alembert's Principle formulated in terms of virtual displacements rather than real displacements in time?


Which formulae should I use when calculating the frequency of an electron given its speed?

$\lambda=\frac{2h}{p}$ instead of $\lambda=\frac{h}{p}$?


Confusion over QM Free Particle Propagator - Shankar 5.1

Free particle Schrodinger equation: propagator


Line emission spectrum of gases and solids

What are the various physical mechanisms for energy transfer to the photon during blackbody emission?


Why does friction point radially inwards when a car is turning in a circular path?

Why does friction act radially inwards when a car turns?


Net Force of Equal and Opposite Gravitational Forces Don't Equal Zero?

Given Newton's third law, why are things capable of moving?


How do the Weyl spinors differ from dotted and undotted spinors?


What is time, does it flow, and if so what defines its direction?


Can a high entropy (heat death) dynamical system spontaneously arrive at a state of low entropy given enough time?

Is heat death reversible by thermal or quantum fluctuations given an infinite time?


Electrics fields in Electromagnetic waves


What's the difference between centre of mass & centre of gravity for massive bodies?


Is it really possible to break the speed of light by flicking your wrist with a laser pointer?


Voltage inside a Cylindrical Capacitor - Dealing With Signs


Was the singularity at the big bang a black hole?


If two identical balls were dropped from the same height, but one of them was given a push to the side also, which would hit the ground first and why?


Why does a bullet shot from a gun take so long to fall?


Why is there a $1/2$ factor in the surface tension for a thin film?


How can a tree fill a coconut with water?

How is it possible for tall trees to pull water to heights more than 10m?


How force affect the objects that we apply on?


How to recover the Newtonian gravitational potential from general relativity?

How can we recover the Newtonian gravitational potential from the metric of general relativity?


Is there any way to see that $H= p^2 +x^2$ has level-spaced spectrum from the symmetry?

Why are the energy levels of a simple harmonic oscillator equally spaced?


Confusion about why sine/cos is used to represent SHM


Why is there no absolute maximum temperature?


How do we know that entanglement allows measurement to instantly change the other particle's state?

How do we know a quantum state isn't just an unknown classical state?


What is the temperature of the black night sky, outside the atmosphere?

What is the temperature of the clear night sky from the surface of Earth?


Bending of light Ray in radially varying refractive index


Why does torque point perpendicular to direction of the motion?


How can I get the axes of the polarization ellipse from the Jones vector of the light?


why doesn't EM waves get weaker as we travel further away from the source

Why do electromagnetic waves become weaker with distance?


Does the wavefunction probabilities have to sum to 1?

Who is doing the normalization of wave function in the time evolution of wave function?


Is the speed of light greater if traveling at an initial velocity greater than zero?

If I am travelling on a car at around 60 km/h, and I shine a light, does that mean that the light is travelling faster than the speed of light?


How do fundamental constants determine the size of material bodies?

Is it possible to speak about changes in a physical constant which is not dimensionless?


Why is the Moon's Centre of gravity different to its centre of mass?

What's the difference between centre of mass & centre of gravity for massive bodies?


Why does less friction in a wheel result in more speed?

Does rolling friction increase speed of a wheel?


Is the temperature of a gas affected by the motion of its container?


How big is the universe 1 second after the Big Bang?


Will a wheel keep rolling in perfect vacuum?


How can a wooden spoon be used to prevent water from over boiling?


Why alternating current produces electromagnetic waves?

How and why do accelerating charges radiate electromagnetic radiation?


Why is a temperature gradient set up in a heated rod?

Temperature at different points in a metal rod during heat conduction


If gravitation force varied with $r^{-3}$ instead of $r^{-2}$ what would happen to Kepler's laws

Conservative central force and stable orbits


Would someone be able to see where they are headed once they crossed the event horizon?

How does light behave within a black hole's event horizon?


Escape velocity from a rotating black hole


How can magnets be used to pick up pieces of metal when the force from a magnetic field does no work?


Equations behind mist formation around wings of fighter jet while doing acrobatic turns

Why can a contrail only form below -40 degree Celsius?


How do we measure the age of the universe?


Compound microscope vs astronomical telescope


When we burn a wood it burns with flame although it do not contain any gaseous substance


Is there a distinction between rest mass and relativistic mass for photons?


Why do we fall towards earth and not hover during free fall as per General relativity?

How does "curved space" explain gravitational attraction?


Is the current in a resistor different from that in a circuit?

Is the current obtained using Ohm's law that which passes through the resistor or that which passes through the circuit?


What does work function of metal exactly mean in photoelectric emission?


Does static friction do work on an accelerating car?


Capacitance of spherical capacitor when earthed


Why is the Lagrangian defined as $L=T - V$?

Is there a proof from the first principle that the Lagrangian L = T - V?


Does the shape of the Universe refer to the curvature of spacetime in 5-dimensional space?

Universe being flat and why we can't see or access the space "behind" our universe plane?


Is there an analogue of the Casimir effect for gravity?

Is it theoretically possible to shield gravitational fields or waves?


Why are so many physical laws expressed in terms of *integer* powers of some quantities?

Why do most formulas in physics have integer and rational exponents?


What is the expression for translational kinetic energy of REAL GAS?

Is expression for law of equipartion of energy valid for real gas?


Why is a unified field theory necessary?

Why do we need a Theory-Of-Everything (TOE)?


What are the charges of all planets in our solar system?


Can Current move without potential difference?

How electric currents can flow between 2 points at the same potential?


Does quantum mechanics mean that there are a finite number of colours?

Is there an infinite amount of wavelengths of light? Is the EM spectrum continuous?


Thus it is proved that there is no such a thing as magnetism


Is it possible that a black hole has a universe in itself?

Do new universes form on the other side of black holes?


Why is work done by non-conservative force around a closed path not zero?

Does it take energy to move something in a circle?


Why do physicists dislike Naked singularities?


Trying to prove Heisenberg's uncertainty wrong

Why can't we use entanglement to defy Heisenberg's Uncertainty Principle?


What does the notation $8.9875517923(14)$ mean?


Perpetual machine from a PN-junction diode

Why isn't there a potential difference across a disconnected diode?


Why does linear motion not emit gravitational waves?

Why gravitational waves are not produced by objects moving at constant velocity?


Why the lighter gas, nitrogen, does not rise above oxygen in Earth's atmosphere?

Why Nitrogen is still (almost) 3 times as abundant as Oxygen in Troposphere?


Schwarz Inequality Proof Using Dirac Notation

Cauchy-Schwarz inequality in Shankhar's Quantum Mechanics


What is the effect of a wormhole on the gravitational field of a large body?

Do gravational effects 'travel' through a wormhole?


Why are oscillations so ubiquitous in nature?


Why Air bubble are always sphere in shape?

Why sphere minimizes surface area for a given volume?


Why do prisms work (why is refraction frequency dependent)?


Can quantum entanglement provide a faster way of transfer of information than the speed of light?

Quantum entanglement faster than speed of light?


Why can't we harness the energy of lightning?

Can the lightning be captured and used as power source?


I want to know more about this specific perpetuum mobile

What prevents this magnetic perpetuum mobile from working?


Is it true that we are probably Boltzmann brains?

Is the Boltzmann brain problem really clearly established as a problem?


The sign of $d\mathbf{r}$ when integrating the universal gravitational force in order to define gravitational potential energy


Can you please explain the statement in the David Morin's Classical Mechanics?


What causes a force field to be "non-conservative?"


What does it mean to take the tensor product of two reps of the Lorentz group?

Vector spaces for the irreducible representations of the Lorentz Group


Difference between Capacitor and a battery

What is the difference between a battery and a charged capacitor?


Are all lengths multiples of the Planck length?

Does the Planck scale imply that spacetime is discrete?


Velocity is to speed as acceleration is to ________?


What would be the associated wavelength of the particle if its velocity is zero?


Dirac Delta Function and Schwarzschild Singularity


Connection between Group of Schrodinger equation and energy level degeneracy

What is the relationship between symmetry and degeneracy in quantum mechanics?


What is the magnetic field of a radially moving current?

Why is the magnetic field of a spherically symmetric current zero?


How to calculate inertia tensor of composite shape with angle?

How to calculate inertia tensor of composite shape?


What is the need of complex functions in wave analysis?


Reducing the degrees of freedom of a Lagrangian in a spherical potential by using integrals of motion


Thermodynamics of early universe - proton and neutron ratio

What is the reason for the shift in balance between neutrons and protons in the early universe?


Why are anticommutators needed in quantization of Dirac fields?


Diagrammatic Representation of non-Gaussian perturbation expansions

Perturbation expansion with path integrals


Why is $p_\phi$ conserved in a Schwarzschild orbit?


Is jumping the result of normal force or action-reaction?


How are images in a telescope finite rather than just a point?

If a lens focuses all incoming light to a point, how do we get 2D images?


Why is the term "information" used to describe a physical system


How far are we from the "edge" of the universe?

Does the universe have an edge/boundary/barrier? If yes, what is at the edge?


How does a wire's magnetic field appear as an electric field, when the wire is neutral?

Moving wire relative to stationary charged particle


Tendency of rotation of an object in space


Why is $SU(3)$ and not $U(3)$ the correct gauge symmetry?


What is difference between rolling, kinetic and static friction?


Why does this rocket stop rolling while going up


Could dark energy and gravity be explained as same phenomenon?

How do we know dark matter isn't curved spacetime?


Why do electrons move in a straight line in a Crookes Tube?

Crookes' Maltese Cross Tube and the anode


Why electron moving with acceleration around nucleus is not emitting EM-waves?

Why don't electrons crash into the nuclei they "orbit"?


Why do black bodies or black colored bodies cool down faster than white ones?


Does work done by a force change when initial velocity is different?

In calculating work done by a constant force over a constant distance, why doesn't the subject's initial velocity matter?


Simple Harmonic Motion - spring with mass

effect of mass of spring on period of oscillation


Are the gradient field are the only fields which are only conservative?

What causes a force field to be "non-conservative?"


Why do we have energy loss same for every length of wire in capacitor charging

A problem of missing energy when charging a second capacitor


How can the total amount of energy in the universe be zero?

Is it always possible to define energy of a system?


Quantum entanglement, how do we know there was no spin?

Quantum entanglement and spooky action at a distance


Abrupt changes in direction and loss of energy

velocity of an object after leaving a ramp


Can an electron jump to a higher energy level if the energy is insufficient or exceeds the $\Delta E$?


Conversion of electrical energy to heat in a circuit


The relationship between $\psi$ and $\bar{\psi}$ in QFT

Can we treat $\psi^{c}$ as a field independent from $\psi$?


Can quantitative model explain away our world?

Can we simulate the whole universe in computer?


Is it theoretically possible to shield gravitational fields or waves?


Can you destroy the Sun if you throw enough iron into it?

How much iron would I have to shoot into the Sun to blow it up?


If information is conserved, why did the early universe had lower entropy than now?

Why does the Coarse-grained Entropy increase?


Does electric field rotates with moving electron, due to spin? Does spin influence on electric field at all?

How does a spinning electron produce a magnetic field?


How to draw a line between observation and minds?

What is an observer in quantum mechanics?


Estimating the minimum hole size for leakage through a sealed membrane

How to find out the maximum radius of a hole that can keep water stay in a container by water viscosity?


Is torque as fundamental a concept as force?


If we see only the reflected colour, how coloured shadows are of same colour?

Why doesn't the orange light filter appear bluish if it transmitts orange and reflects or absorbs all other frequencies?


Why is the phase difference an "odd number of half-wavelengths" when two waves interfere destructively?

Are two waves out of phase only when the phase difference is $\pi$?


What theoretical explanations exist for the absence of any observed gravitational magnetism?

Why is there no gravitational magnetic field? (Or, is there?)


How are different parts of an extremely fast spinning disk affected by time dilation?

Can a ultracentrifuge be used to test general relativity?


Does the effect of field travels faster than light?


Why distance equals initial velocity times time Plus acceleration over two times time Squared?

Why there is a $\frac{1}{2}$ in the distance formula $d=\frac{1}{2}at^2$?


How to compute $\langle n'| (a^++a)^k | n \rangle$ for arbitray $k$?

Exponential of ladder operators acting on a Fock state


Is it experimentally verified that elementary/fundamental particles don't have temperature?


What is the difference between the two time derivatives $\frac{\text{dL}}{\text{dt}}$ and $\frac{\partial \text{L}}{\partial \text{t}}$?

What is the difference between implicit, explicit, and total time dependence, e.g. $\frac{\partial \rho}{\partial t}$ and $\frac{d \rho} {dt}$?


What happens to the energy when I push my hand against a wall but there is no displacement? How to calculate it?

Where does the energy get transferred when we push the wall?


While space itself expands, why does it seem to expand more between the stars than between me and my desk?

Why does space expansion not expand matter?


What implications does special relativity have on the accelerating expansion of the universe?


What's pressure in the stress-energy tensor?

Intuitive understanding of the elements in the stress-energy tensor


References about the application of group theory in physics

Simple applications of group theory which can be understood by a senior undergrad


Why do I see a saddle in this picture of a computer screen?


How to prove gravitational force inside a hollow sphere is zero?

Gravitational field intensity inside a hollow sphere


In what situations would it be more beneficial to use Newtonian Formalism vs Lagrangian Formalism?

What is the difference between Newtonian and Lagrangian mechanics in a nutshell?


Speed of Dark experiment, does it *really* travel faster than light?


Why is Gibbs Free Energy not equal to 0? Its definition itself makes it 0


Why is the Sun the centre if relativity is true?

Why do we say that the Earth moves around the Sun?


The centripetal acceleration is directly or inversely proportional to the radius?

How is centripetal force related to radius?


Is the inflation theory based on the inflaton field or electronuclear force carriers decay?


Ohm's second law: step by step to obtain this law


What is exactly the density of a black hole and how can it be calculated?


Intuitive explanation for why blue light is refracted more than red light?

Why do prisms work (why is refraction frequency dependent)?


When spacetime is being curved, Does that mean it is moving?

Better explanation of the common general relativity illustration (stretched sheet of fabric)


Is there any method to know the real age of the universe?


How inflation explains the missing monopole?

How does Inflation solve the Magnetic Monopole problem?


How can there be acceleration but no velocity at instant of maximum height when object projected upwards?

Why isn't the acceleration at the top point of a ball’s journey zero?


How fast a (relatively) small black hole will consume the Earth?


What happens at the molecular level when a spring is being extended?

Why is the restoring force directly proportional to extension?


How does the current remain the same in a circuit?

If current is same, is it correct to say that the speed of charge passing through a resistor is more than that of a normal wire?


What is the sum of internal angles of a triangle around a black hole?

What is the sum of the angles of a triangle on Earth orbit?


How to prove that all eigenstate $|0\rangle,|1 \rangle,...| n\rangle $ are non-degenerate?

Proof that the One-Dimensional Simple Harmonic Oscillator is Non-Degenerate?


Can the Higgs particle escape a black hole?


Expansion of the Universe (within galaxies)

Can the Hubble constant be measured locally?


If an observer changes their velocity, is it equivalent to a momentum shift?

Galilean invariance of the Schrodinger equation


What is the potential energy of the spring?

Why I think tension should be twice the force in a tug of war


Gauss' Law Generalization to all closed surfaces

How is Gauss' Law (integral form) arrived at from Coulomb's Law, and how is the differential form arrived at from that?


Physical intuition of solid angle of a closed surface

Why solid angle of a closed surface from exterior is zero?


Are induced electric field lines circular in nature?


Relation of liquid pressure with breadth

Pressure and weight? (hydrostatic paradox)


How is $\mathrm dU=C_V\,\mathrm dT$ always true?

$\Delta U$, $C_p$, $C_v$ for an ideal gas process


If an electron is a singularity do we talk about a black hole?

Are electrons just incompletely evaporated black holes?


Symmetry of the $3\times 3$ Cauchy Stress Tensor


Why can we approximate the rays as parallel in a diffraction grating for a maxima?

When deriving $d\sin\theta=n\lambda$ are the light rays approximately parallel or actually parallel?


Complex conjugate Young Tableaux representation

Complex conjugated representation and its Young tableaux


Could String theory / CFT be classified as pseudoscience in its current form?


Calculating the distance crossed by a ball under changing gravitational acceleration

Integrating radial free fall in Newtonian gravity


Adding many more neutrons to a nucleus decreases stability?


What is the force of friction on the body?

How does one calculate frictional force for an object sliding down a wall?


What if humans doubled size... and everything else... could we notice?

If everything in the universe doubled in size overnight, would it be noticeable?


What is exact definition of potential energy if all forms of energy except kinetic comes under potential energy?


Why does electron $(-)$ keep rotating round the nucleus $(+)$ even they are attracted?

Why don't electrons crash into the nuclei they "orbit"?


Explanation of Different factor of $2$ in Formulas for the Uncertainty Principle

Factor 2 in Heisenberg Uncertainty Principle: Which formula is correct?


Differences between pure/mixed/entangled/separable/superposed states


Is this equation for mass defect correct?

Correct formula for Mass Defect / Binding Energy?


Why is the electric current is a scalar quantity?


Two electron beams exert different forces on each other depending on frame of reference?


Does the Planck scale imply that spacetime is discrete?


Does a Faraday cage block outgoing signals?


Rotation of rigid body with two different angular velocities


What happens when the centripetal force is equal and opposite to the centrifugal force?

Do centripetal and reactive centrifugal forces cancel each other out?


Black holes and positive/negative-energy particles


Do magnets lose some form of energy while attracting each other?

From where do the permanent magnets get energy from?


If movement is relative, why is it said that moving objects have kinetic energy?


What is the force between two charged objects when the space between them is partially filled by a dielectric medium?


Could someone explain what it means that temperature is a lagrange multiplier of energy?

Is temperature a Lagrange multiplier of energy?


Is there a physical connection between Lagrangian mechanics and Hamilton mechanics

Physical meaning of Legendre transformation


What is $c$ in the Lorentz force expression?


How big would the moon appear with no atmosphere?

Why does the moon appear bigger close to the horizon, rising or setting?


The actual period of a pendulum at 90°. Looking for the correct formula


Given Newton's third law, why are things capable of moving?


Why is frosted glass reflective at an angle?

Why is there a clear mirror image off a rough surface at shallow angles?


How can we see incoherent light at all if waves interact?


Why did this table tennis ball rise to the sky?

Floating a ping pong ball in the air just using a pen!


Why only 2 derivatives in classical mechanics?

Why are differential equations for fields in physics of order two?


What is your simplest explanation of string theory?


Time to collide of hammer vs Moon, feather vs Moon, considering that the Moon is attracted by them (barycenter)

Don't heavier objects actually fall faster because they exert their own gravity?


Why visible light satisfies Maxwell equations?

What is the experimental evidence that light is an electromagnetic wave?


Where does the energy get transferred when we push the wall?

Why does holding something up cost energy while no work is being done?


Why does no physical energy-momentum tensor exist for the gravitational field?


Is this possible to build a quantum network?

Quantum entanglement faster than speed of light?


Photoelectric effect: Beginning of the complexities

Photoelectric Effect, Why can't two quanta interact with an electron at the same time?


Why is that in quantum mechanics quite often the physical observable is represented by Hermitian operator?

Why are Hermitian operators linked to observables?


Why does the beam in a weighing balance get tilted proportional to the weights added to each pan?


How to get space component of weak field (linearized) metric?


If neutronium existed out there, are we capable of observing it?

How would neutron matter appear to the naked eye?


How the world changes from the point of view of a photon

How does a photon experience space and time?


Are photon rest frames distinguishable from other inertial frames?

Does a photon in vacuum have a rest frame?


Confusion on the indice of refraction: is it dependent on the frequency or not?

Intuitive explanation for why blue light is refracted more than red light?


Is it possible for physical constant to change in time?


Is Maxwell's theory of electromagnetism completely validated?

Have we directly observed the electric component to EM waves?


Why is $\langle \hat{A} \rangle = tr(\hat{\rho} \hat{A})$?

Why is $\langle \textbf R \rangle =Tr \rho R$ here $\rho$ is the state density matrix


Why does time dilation even occur? Confusion


Proof that total orbital angular momentum square can only take integer values of $\hbar^2$

Why is orbital angular momentum quantized according to $I= \hbar \sqrt{\ell(\ell+1)}$?


Do we understand why mass, charge or magnetic moment appear as quantized quantities?

Reason for the discreteness arising in quantum mechanics?


Why doesn't dark matter collapse into a black hole?

If dark matter only interacts with gravity, why doesn't it all clump together in a single point?


Why don't solid objects blend into each other?

How can I stand on the ground? EM or/and Pauli?


The Time That 2 Masses Will Collide Due To Newtonian Gravity


How does Susskind get this fourth equation?

How to get the fourth component of EOM in a relativistic formulation of a charged particle in an electromagnetic field?


A list of inconveniences between quantum mechanics and (general) relativity?


Is escape velocity really a velocity (rather than a speed)?


Pressure exerted by a liquid on the bottom of a submerged object

How does the buoyant force on a cube at the bottom of a tank of water manifest itself?


Einstein-Cartan Theory with modern Cartan structural equations?

Einstein-Cartan theory - Book recommendation


what is the Equation of State for a perfect solid?

Is there an Ideal Liquid Law? Or Solid Law?


Blocking of infrared radiation from the sun by $\rm CO_2$

How does carbon dioxide or water vapour absorb thermal infra red radiation from the sun?


What quantum mechanical property allows for reflection?


Why don't electrons crash into the nuclei they "orbit"?


Why angular velocity is a vector quantity?

How is it that angular velocities are vectors, while rotations aren't?


Gravitational Time dilation for motion in a gravitational field


What is the correct formula for drift speed of electrons

Which derivation of drift velocity is correct?


How did Newton know that there is force between two mass?

How did Newton discover the universal law of gravitation?


Why should an action integral be stationary? On what basis did Hamilton state this principle?


What if the size of the Universe doubled?


Atwood's machines: acceleration of massless pulley

For a massless pulley moving upwards with acceleration, is the upward force equal to the downward force?


If I could stop ALL motion would I stop time?


Why does paint mix to produce black, but light mix to produce white?

Why does mixing every paint colour produce gray instead of white?


How do I find the longitude of the subsolar point?

Is there a simple yet accurate formula for where on Earth the Sun and Moon are directly overhead?


Why the free electrons in space can not be excited by photons?

Can a free particle absorb/emit photons?


How does law of reflection work at the atomic level?

Explain reflection laws at the atomic level


A simple explanation of Kepler's Third Law


How would we calculate the dipole moment of a charge combination (of 3 or more charges) whose magnitudes are different but net charge is zero?

Meaning of the phrase "dipole moment of the combination"


How is red shifting explained with quantum mechanics?


Does a photon exert a gravitational pull?


Can someone explain the Navier Stokes equations?

Can you explain Navier-Stokes equations to a layman?


why isn't conservation of energy just a definition?


Solutions locally isometric to Schwarzchild


What are the 'types' of parametric down conversion?


If a massless observer is going at the speed of light, what speed will it measure of a light beam going parallel to it?

Does a photon in vacuum have a rest frame?


What does it mean for two objects to "touch"?


Could Alpha Centauri be made of anti-matter?

How would we tell antimatter galaxies apart?


Different statements of the Heisenberg uncertainty principle

What is $\Delta t$ in the time-energy uncertainty principle?


How would one represent/model the effect of air resistance on horizontal motion?

Explanation that air drag is proportional to speed or square speed?


What is the speed of electricity in a vacuum?

Accelerating particles to speeds infinitesimally close to the speed of light?


Conflicting models about how energy transferred in an electric circuit

In a simple battery + resistor circuit, what form of energy is lost from the electrons upon exiting the resistor?


How is the electromagnetic/gravitational force transmitted?


Why dont radio waves diffract through radio telescopes instead of being reflected?

Why can radio telescopes use wire mesh as their parabolic dish?


How to explain Newton's second law using Lagrange's equation?

Calculus of variations -- how does it make sense to vary the position and the velocity independently?


Given Newton's third law, why are things capable of moving?


What has general relativity got to do with special relativity?

What is the connection between special and general relativity?


If a mass moves close to the speed of light, does it turn into a black hole?


Would possibility of instant communication break physics?

What are some scenarios where FTL information transfer would violate causality?


Why charges should go to the surface of conductor?

Why are excess charges in a conductor at the surface?


What kind of matter are black holes made of?


Why do all atoms follow the same $n$ and $\ell$ quantization conditions as hydrogen?

Why do non-hydrogen atomic orbitals have the same degeneracy structure as hydrogen orbitals?


How can speed of a gaseous molecule be approximately equal to infinity?

What is the correct relativistic distribution function?


Is the wave-particle duality a real duality?


If electromagnetic waves have magnetic fields, why beam of flashlight is not disrupted by a Magnet?


Newton's 3rd law... hitting drywall (which I break) vs hitting a brick (which breaks me)?


Positron-electron annihilation - can more than two photons be created?


Antiparticles travelling backward through time

Is anti-matter matter going backwards in time?


Gauss's law in a uniform charge distribution extending infinitely in all directions


Delayed eraser experiment (Kim experiment)


Why can't we see Rainbows from its end points?


What is the significance of kinematic viscosity?


Are Imaginary Numbers Really “Imaginary?”


How should a physics student study mathematics?


What determines which frames are inertial frames?


Mathematics of quantum mechanics for beam splitter

Phase added on reflection at a beam splitter?


Why is the direction of net force on an object and the direction of acceleration of that object is different in this situation?

Why is the direction of net force on an object and the direction of acceleration of that object different in this problem?


Why do planets revolve around Sun in elliptical orbits?


Is a finite lightspeed necessary for cause and effect to exist?

In what subfields and how far can the naive limit $c\rightarrow\infty$ of special relativity be carried?


Constant acceleration space travel: velocity relative to the Earth?

Does the pilot of a rocket ship experience an asymptotic approach to the speed of light?


About which point should the torque be calculated?

The choice of pivot point in non-equilibrium scenarios


How to derive a formula for the period of a simple pendulum?


What is the relationship between time dilation and gravitational time dilation?

Is gravitational time dilation different from other forms of time dilation?


Is it possible to drain all oceans' water to space?

A water pipe from sea level to beyond the atmosphere


Is gravitational constant a rational number?

Is speed of light and sound rational or irrational in nature?


Simple harmonic motion phase difference problem

Which equation to use for simple harmonic motion?


Can Noether's theorem be applied to cyclic time symmetries?

Is there something similar to Noether's theorem for discrete symmetries?


Books recommended as requisites for understanding general relativity to the fullest?


Is there an easier guide or something to George Arfken's mathematical methods for physicists?


Why is an electromagnetic wave represented by two perpendicular sine waves instead of a sine and cosine?

If time-varying electric and magnetic fields originate each other, how come they are in phase?


Best self-study books for static mechanics problems


How quickly is momentum transferred through an object?

Is it possible for information to be transmitted faster than light by using a rigid pole?


Looking for a textbook on electromagnetism

Recommended books for advanced undergraduate electrodynamics


Why do we derive more fundamental quantum theories from less fundamental classical theories?

Quantum systems without a classical analogue?


Why are mesons only made of a quark-antiquark pair?

Why do quarks tend to bond in groups of three?


Why does water always take an already travelled path?


How do you know when two objects are entangled?

How can we know if a pair of particles are entangled?


How to differentiate permanent age difference in the twin paradox from reciprocal time dilation?

What is the proper way to explain the twin paradox?


Why the faster you spin the highest the pitch get in a whirly tube?

Why does the fundamental mode of a recorder disappear when you blow harder?


A flying fly inside a sealed box on a scale


Coulomb's Law: why is $k = \dfrac{1}{4\pi\epsilon_0}$


Erratum in Griffiths Electrodynamics (wrong reference is made)

Erratum in Griffith's Introduction to Electrodynamics


Why do Fermions (quarks specifically) have transversity while Bosons (gluons specifically) don't?

Why is the $S_{z} =0$ state forbidden for photons?


Why can't magnetic field lines intersect with each other?

Why can two (or more) electric field lines never cross?


Would visible light still be in a separate classification if we saw "colors" in a different wavelength?

Is there a physical reason for colors to be located in a very narrow band of the EM spectrum?


Work done by static friction in accelerated pure rolling motion

How can friction do no work in case of pure rolling?


Heisenberg's principle in classical world

If an object is large enough and slow enough is there a point that we can say we know its position and momentum?


Are there systems in classical mechanics that are provably non-deterministic?

What situations in classical physics are non-deterministic?


Can angular velocity and angular accelaration about any two points of a rotating body differ?

How rotating body have same angular velocity and acceleration


Is power equal to $\vec{F}\cdot\vec{v}$ where $\vec{F}$ is force and $\vec{v}$ is velocity?

Why isn't the product rule used in the definition of mechanical work?


Is the universe expanding, or is everything in it getting smaller?

How do we know the universe is expanding, and not that its contents are shrinking?


Rigid bodies: angular velocities, momentum, Inertia Tensor, rotational kinetic energy. Books suggestions?

Recommendations for good Newtonian mechanics and kinematics books


Is gravitational time dilation nothing more than kinematic time dilation in another form?

Is gravitational time dilation different from other forms of time dilation?


Why doesn't the atmosphere separate according to density?


What is the source of the electric field in a RF cavity that causes particle acceleration?


Are impacts in outer space more powerful than on Earth?


Forced Oscillations: What exactly is happening?

A conceptual doubt regarding Forced Oscillations and Resonance


What will happen to speed of light in an accelerating frame?

Does the speed of light vary in non-inertial frames?