New answers tagged

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 ...


3

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? ...


1

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 ...


0

If the event horizons overlap you get one big horizon. EM forces can not counteract gravity if the curvature is too large since the force required to counteract gravity becomes infinite at the horizon. You can see this in the equation $$F=\frac{G\cdot M\cdot m}{r^2\cdot\sqrt{1-r_s/r}} $$ which becomes infinite at the horizon $r_s$. Since from the outside ...


0

To question 2: When the electron reaches the end of a conductor, it would have to move into the air, which is an isolator. The entire conductor is at equal potential, which is much much lower than the potential at a point out in the air. So it reaches the end and stops, since it is only driven by the potential difference $$F=\frac{dU}{dx}$$ in it's rush to ...


0

In the situation you depicted, the electric field is different from $0$ in the hollow region enclosed by the conductor and equal to $0$ inside the volume of the conductor (at equilibrium). Why is $\vec E = 0$ inside the volume of the conductor at equilibrium? We will proceed by reductio ad absurdum. Since we are at equilibrium by hypothesis, there can ...


1

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 ...


0

I would answer this question differently. From other perspective, a electron gets its charge by the only generator that is not broken after the S.S.B of the SU(2)xU(1) gauge group. In this case $$ Q = \frac{1}{2} Y + T_{3} $$ Where $ Y $ is the hypercharge eingevalue and $ T_{3} $ is the eigenvalue related to the SU(2) diagonal generator. So, as every ...


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 ...


0

An electron is a fundamental particle(Lepton) and is different from both protons and neutrons, which are not fundamental(i.e they are made from even more smaller particles called quarks). For an electron, the charge it has is an intrinsic property, that is it is a part of its description along with mass and spin. Coming to neutrons and protons, even though ...


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 ...


1

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 ...


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 ...


0

looks to me like the answer you have been given is incorrect. The way I see it you have a C of approximately $18 nF$ The electric field is the voltage divided by the gap - so the voltage across the capacitor is $200 V$. Now you can use $Q=CV$ to get $Q=3.6\mu C$ (actually $3.5$ probably I just did an approximate calculation to check your working)


0

You are not the first to try think that one more undelying onion level ( or matriuska) lies within what are considered fundamental particles at present. Back in the late 1970s when the quark model was established , preons were the next hypothesis as the subcomponents of quarks A number of physicists have attempted to develop a theory of "pre-quarks" ...


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 ...


0

Electrons and other leptons are, as far as we know, fundamental. They are not made out of quarks, they are not made out of anything! Neither of your assertions has any empirical evidence going for it. However, it seems you are really asking for reasons for charge discretization, since you seem to get the idea of your assertions from the charges of electrons ...


1

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 ...


1

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 ...


0

The concept of electric charge is introduced to explain experiments (originally from static electricity). It is found that only two types of charges are necessary and to distinguish them and to distinguish between they are given labels. The most convenient label is positive and negative (that has some mathematical advantages). It is pure convention that ...


-2

If the electron is said to be a charge carrier seems to be a little bit misleading. Electrons have the intrinsic property of electric charge, they are a charge. You can’t take away the charge from the electron, the electron is the charge. And as long as there are not found constituents of the electron it makes no sense to talk about a carrier property. ...


-1

All particles seems to be grouped under two distinct polarities based on the manner of attraction or repulsion. Those particles repelling one another are said to have like charges. Those that attract one another have different charges. Being a positive or negative charge, is a matter of convention already accepted by world scientific community. A Charge is ...


0

Electrons have charge, and that's not going to change, as you said. There are interactions that involve the charge going one way and something else going another way. One example would be reverse beta decay - Electron and a proton come in, neutron and neutrino go out (other particles will get involved, depending on the details). The neutrino carries the ...


-1

I don't know validity of my answer but still I would liked to propose it. What is the maximum energy you can extract from an electron here In above question we see their is a limit to energy we can extract from an electric field due to finite charge. If you somehow extract all that energy, you can eliminate its electric field and hence it is equivalent to ...


0

As I read your statements, I get the impression that the difference between capacity and capacitance is not clear to you. The capacity of a capacitor is defined by its "physical" construction (length, width, area, volume, material, etc. C = kA/d). However, capacitance is a measure of how difficult/easy it is for a capacitor to store charge (C = Q/V , ...


0

Electrons have a drift velocity which is very small. But electrons pass the charge. They do not flow with a charge on it. It's like dominoes that fall. The energy wave propagates through the falling dominoes, but the dominoes don't translate much. Also it doesn't matter who is propagating the charge. Electrons and protons and charged ions- all can do that. ...


3

According to the rules of qft there are virtual photons in the vacuüm. 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 ...


0

The Earth's surface is negatively charged and the ionosphere is positively charged. This results in a downward electric field of strength of the order of 100V/m at the Earth's surface. This is the "fair weather" value and assumes that there are no conductors close by. Well you are a fairly good conductor of electricity and so when you stand on the ground ...


0

As another answer pointed out, your formula is for electric field around an isolated point charge. It doesn't apply to the case of parallel plate capacitor. Normally we use Gauss's Law to find the electric field between the plates of the capacitor. We know that the field between the plates will be uniform from the differential form of Gauss's Law ...


0

You reference the equation giving the electric field near a finite point charge. There is no finite point charge in a capacitor (unless we count a single electron, but I think you'll find a single electron won't produce a very large field measurement on a human scale...). The charge is distributed uniformly, and as you (you're a test charge) get closer to ...


-1

there are lots of questions and explanations, why the field of an infinite plain is homogeneous and does not depend on distance. That is the approximation involved: that the plates are big. So outside the plates the fields add to zero, and inside it's double. No, charge is not brought from one plate to the other. If you have an alternating current, it will ...


-1

In my understanding, the free charge is any charged particle that is not being restrained in the boundary, while the bound charge is in the boundary.It does not matter whether the material you currently discuss is a dielectric or a conductor.


1

For instance, why don't measure the ability to store something by the volume it takes so why not charge per unit volume. There is nothing wrong with you defining a parameter which is the "charge per unit volume" but after defining it then what are you going to do with it? So here you have a capacitor and its charge per unit volume is $3 \;\text{C ...


2

I understand that capacitance is the ability of a body to store an electrical charge and the formula is $C = {Q \over V}$ Perhaps you just need to top thinking of capacitance as that. "Capacitance" sounds like "capacity", which leads to an intuitive trap like this: If I have a basket with a capacity of 2 apples, then a basket with more capacity can ...


3

We Use $C=Q/V$ because those were useful things to measure. It's often easy to forget, but many of the equations we use are chosen because the work, and because other equations didn't work. Never underestimate that part of the reality. We don't use "charge per unit volume" because that number is not constant. You can charge a capacitor up without ...


23

You can use a high vertical tube to store water in it (fill it from the bottom by pushing the water in) How much water can you store? It obviously depends on the pressure you apply to push it in. If you push harder, there will be more water stored. The tube is characterized not the amount of water, but by how easy it is to store the water. Its "capacity" ...


2

A capacitor is used to store energy in form of electric fields. This electric field is created by charges on plates of capacitor. So, basically you are storing charge on capacitors. Let someone ask you how much charge you can store in your capacitor.What would you reply? Clearly , you reply " I may store 1mC or 100mC, depending on Potential difference ...


4

Capacitance is "charge over voltage" – and one farad is "coulomb per volt" – because the capacity of capacitors (something that determines their "quality") is the ability to store a maximum charge on the plate ($+Q$ on one side, $-Q$ on the other side) given a fixed voltage. When you try to separate the charges, you unavoidably create electric fields ...


1

why would increasing voltage, while keeping charge constant, have any effect on the ability of a body to store charge. (1) Capacitors don't store charge, they store electrical energy. For a capacitor, it is understood that one plate has charge $Q$ while the other plate has charge $-Q$ so there is no net electric charge stored. (2) If you increase ...



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