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5

As @Tweej suggests, it's because of water solubility. Because water molecules are quite polar, most things that are charged or polar are soluble in it (i.e.~"hydrophilic"). When a coffee stain dries up, the residue sticks to the surface. But when water is applied, it will readily mix with the water, and more easily be removed. Fats and oils are ...


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It is one of the experimental observations that led to the standard model of particle physics. The model has symmetries ( SU(3)xSU(2)xU(1) ) that build up the representations and these allow only for integer multiples charges, i.e. are consistent with observations. For example, why is there no meson existing of two up quarks, giving a charge of 4/3? ...


3

According to the rules of qft there are virtual photons in the vacuĆ¼m. No, according to QFT the vacuum is static, in the sense that $P^\mu|\Omega\rangle=0$. Or put it another way, The vacuum at a time $t$ is exactly the same vacuum at a time $t+\Delta t$ for any $\Delta t$. This means that the picture of particles constantly appearing and disappearing ...


2

The RHS side of Gauss's Law, that is the charge enclosed should remain the same is indeed true. The apparent confusion if any, should be in the LHS of the equation, the integral of the 'dot product' of field and area vectors. Consider the diagram, Now, when we take the dot product of the field vector with the area vector in the initial case, the field and ...


2

Potential refers to a particular point - or set of points which are "equipotential". So you can talk about the potential of one of the capacitor plates (because each is an equipotential surface) but not the potential of the capacitor (because when charged the $2$ plates are at different potentials). When talking about a capacitor, potential usually means ...


2

$1~\textrm{Ampere-hour}$ equals $3600~\textrm{Coulomb}$ of charge. The amount of charge a battery can hold is determined by the amount of chemicals that are in it and it's fixed by the design of the battery. Usually it only decreases because of loss of electrolyte or changes in the chemical and physical structure of the electrodes. The voltage on a ...


2

1 How does an electron get its charge? This is the elementary particle table . The electron is an elementary particle and its charge is an observable attribute that , together with its other quantum numbers and mass, classify it as an electron. And how can it maintain that charge for very long (infinite) periods of time? Observations ...


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Traversable - Overlapping (actually intersecting) region would not be Traversable even if the gravity at some parts of the region may be zero. For exampple, between earth and moon, gravity will be zero at some point. That does not mean something in that region can go out of earth/moon system. As soon as an observer leaves that region, it either falls towards ...


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I have found your question and the diagram a little difficult to interpret. I have redrawn you diagram to show a charge of $+Q$ on the outer shell and a charge of $-Q$ at the centre together with two conducting shells shaded grey. What else the electric field inside the conductors is zero. If there was an electric field then the mobile charge carrier ...


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In vacuum, any two point charges bearing electric charge of the same sign will solely interact, if they are pinned at a particular distance, via the Coulomb force that is in $\sim \frac{q_1q_2}{r^2}$ as you say so that they will always repel no matter the distance. Now, if you take in vacuum any two charged pieces of the same material (even at the ...


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Electrons can not loose their charge. It is not currently known to be made up of any other elementary particles, as discussed in the other postings. What makes it impossible are the conservation laws of charge, energy, and lepton number The one for charge would say that if it looses its charge something else has to appear with the same charge. That would ...


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Another derivation is that the action for the field interacting with a current is $\propto\int d^dx A_\mu j^\mu$ while the action for interaction with a particle is $\propto\int A_\mu dx^\mu$ along the worldline. Taking care of the precise constants in front of these expressions, you can see that the formula you write is tailored precisely so that the two ...



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