Electrostatics is concerned with the electrical fields and scalar potentials of stationary electrical charges and charge distributions. Use this for questions about electromagnetic situations in which currents and magnetic fields are absent, otherwise use [tag:electromagnetism] and/or [tag:magnetic-...

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Electrostatic pressure

https://en.wikipedia.org/wiki/Electrostatics says that "This pressure tends to draw the conductor into the field, regardless of the sign of the surface charge." Does this mean that if I place a ...
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3answers
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when current passes through a wire , does it only travel through the outer surface?

In electrostatics we are taught that the field inside a conductor is always zero . So when current passes through a wire , the electricity only passes through the surface of the conductor . In ...
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Electrostatic energy of the system

Problem : $(A)$ There are two thin concentric metallic shells of radius $a$ and $b$ $(b>a)$. Inner shell carries a total charge $Q$ and the outer shell carried a total charge $–Q$. Calculate the ...
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14 views

How to find the polarization (phase) of the virtual source if image theory is used

Consider a radiating element (actual source) is placed above a ground plane, and if we apply image theory to determine the E-filed, the virtual source will be placed below the ground plane and ground ...
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2answers
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Problem understanding energy of a electric field

I just finished classical mechanics, and waves and have started electromagnetism. I have studied upto electric fields, potentials and conductors in a static field and have just entered capacitors. And ...
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3answers
33 views

How to determine the concentration and sign of the charge carriers in copper

I need to design a procedure for an experiment to determine the concentration and sign of the charge carriers in copper. I'm given: A slab of copper 2.0 mm thick, 1.5 cm wide, and 4 cm long One very ...
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2answers
31 views

Static electricity - what is it?

I'm just having some difficulty with completely understanding the concept of static electricity. What actually happens? Is it because the electrons cant move? And if so, why can't they move?
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35 views

Need help with signs (+ -) in electric potential work and potential energy problem

The problem is from Sears and Zemansky's University Physics, 12th edition in Spanish. The problem says: How much work is needed to assemble an atomic nucleus that contains three protons if it is ...
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1answer
53 views

Divergence of $\frac{e^{-br}\hat{r}}{r^2}$ in electrostatics [closed]

My question is how to calculate the divergence of a vector field (Electric field) given as: $\vec{E}(r)=\frac{e^{-br}\hat{r}}{r^2}$. Or more generally how to approach finding the divergence of a ...
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1answer
49 views

Why does there have to be an electric field if there is potential difference?

I read in a few books that there is always an electric field if there is an electric potential. I went through this but the question on this page only states that there is an electric field and it is ...
3
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1answer
31 views

How do flames neutralize a static charge?

I was working with a demonstration galvanometer recently when it accidentally picked up a static charge from me lightly rubbing my hand across it. The case was made of a clear plastic. My attempts ...
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2answers
48 views

Why doesn't the gravitational force have a permittivity in its formula? [duplicate]

We know that the electrostatic force between two charges depends on the medium between the charges and its permittivity. Why, then, doesn't the gravitational force depend on the medium?
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Why does electromagnetic induction creates both voltage and current but static electricity only creates voltage and no current?

Why is it that electrons do not move the same way in triboelectric as in magnetic induction when both creates voltage? Triboelectricity can even create tens of thousands of volts like Van De Graf ...
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Electric field $E$ due to a dipole moment

Why is the formula of $$E = kp/z^3~ ?$$ Why is it $z^3$ ? I want a physics answer not math please.
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2answers
36 views

How to find electric potential from electric field? [closed]

How to find potential difference when electric field is given ?
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1answer
27 views

Force between the plates of a capacitor

As we know that the electric field between two parallel plates of a capacitor is $$E=\frac{\sigma}{\epsilon_0}$$, so the magnitude of force exerted by one plate on the other should have been $$F=QE$$. ...
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1answer
27 views

why potential becomes equal when capacitor are connected

If we have a circuit as shown in which two capacitor are connected of unequal potential. Now if we close the switch the charge will flow till potential becomes equal. But as we know $Q=CV$, $V=Ed$...
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1answer
22 views

Final potential difference between plates of capacitor [closed]

If the plates of a parallel plate capacitor are given charges 4Q and -2Q . The capacitor is then connected across an uncharged capacitor of the same capacitance as first one (=C) . Now we have to find ...
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0answers
16 views

As distance increase why no change in electric field in parallel plate condenser [duplicate]

If the distance between the plates of a parallel condensor is 4mm and the potential difference is 60 volts. Now if we increase the distance between the plates to 12mm, then: Why the electric field ...
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0answers
29 views

Potential Energy for dipole in Electric Field

Potential Energy is the work done by the external agent in turning the angle of the dipole from the U=0 position to another position against the influence of the electric field applied right? So if ...
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2answers
90 views

What moves the charges between capacitors?

Suppose I charged two capacitors to charges Q1 and Q2. By charging a capacitor to charge +Q , I mean that one plate acquires a net charge +Q and another plate acquires a net charge -Q.The capacitors ...
0
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1answer
49 views

Can/will a proton escape the nucleus when a force is applied? [closed]

Protons are contained within the nucleus of an atom. Protons carry a positive charge. With an electric field, we can exert a force on the proton. Is it possible for the proton to escape the nucleus? ...
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1answer
18 views

The direction of electric field in a thin hollow cylindrical insulating shell

Consider a thin hollow cylindrical insulating shell like the one above draw in 3D-coordinate with Z-axis going out of page and is centered at the origin of XYZ axis. It has electric charge +Q ...
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1answer
40 views

Unification of Newtonian gravity and electrostatic force [closed]

Can we not unify Newtonian gravity & electrostatic force? All properties are almost same. We can imagine the atoms of the Earth's core to become dipoles when a body is freely-falling. Thus, due to ...
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2answers
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Should static electricity affect a Crookes radiometer?

I've been playing around with a Crookes radiometer for fun and I happened across something I can't figure out. I know the fundamentals of the radiometer (e.g. partial vacuum, thermodynamics, etc.), ...
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2answers
36 views

Determination of the electric field of charged object using Gauss's law

when we determine the electric field of a charged rod of infinite length,we consider a circular cylinder to be the gaussian surface for convenience.In the case of a charged sheet we choose the ...
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2answers
60 views

Are these capacitors parallel or in series?

I am a bit confused. The authors say these conductors are parallel when the switch is on. But to me it looks like they are in series since the handle is insulating. How can you explain that they are ...
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1answer
34 views

How to Explain the the following situation?

I have thought a simple thing: consider a system of a planet and its natural satellite revolving around it in a perfectly circular orbit(assumed) and this is happening in an isolated space in some ...
2
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1answer
71 views

Does changing a closed surface in the manner outlined contradict Gauss' Law?

As I understand it, Gauss' Law states that the electric flux on any arbitrary closed surface is equivalent to the sum of all charges enclosed within the surface times a constant. Mathematically, this ...
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1answer
18 views

Different charges of plates of parallel plate capacitor

Suppose the plates of a parallel plate capacitor have charges +2Q and -Q initially. Then if they are connected with a battery of emf V what will be the charge distribution on the plates of capacitor? ...
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0answers
16 views

How can I know the induced charge density in a dielectric?

There's an infinite conduciting plane lying over the XY plane, conected to a battery that keeps it at a constant potential $\phi_0$. At a distance $D$ from the plane there is a point charge $q$ that ...
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0answers
35 views

Determine potential function given initial conditions?

Assuming a radially symmetric circular disk (let's say r=1). Given two simple initial conditions: Potential at the centre is 4 V Potential at the edges is 0 V How would I determine the potential ...
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2answers
57 views

Why electric potential at equatorial point of a dipole is 0?

Well ok I know that electric potential at equatorial point of a dipole is 0. It is a derived conclusion. Q1. But how this can be explained "theoretically"? Another question that electric potential ...
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0answers
26 views

AP Physics 1/2- Electrostatics Capacitor [closed]

I recently took a physics exam over Electrostatics Capacitor and was unsure about a couple of questions. the test was free response and I had to explain. Please tell me if my answer and reasoning ...
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1answer
15 views

Relyance of plate distance on the capacitor equation

I am studying capacitors and i cannot seem to understand why the increase/ decrease in voltage and distance between the plates would affect the capacitor's abillity to store charge. Can anyone help??
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27 views

Is it possible to get an analytic expression of the capacitance for this geometry?

Here is the geometry I'm talking about: Assume the red rectangle is at some constant potential V, like 10 Volts, and the blue is at ground. We can assume that the rectangles extend infinitely (to ...
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0answers
95 views

Charge over 2 layer dielectric, image method

If I have a charge $Q$ located over a 2 layer dielectric as represented: According to the image method : the charge $Q'1$ will be located at a distance $h_1$ under the first interface and the $Q'2$ ...
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0answers
12 views

Charges on outer faces of parallel plate capcitor

Can there be charges on outer charges of a parallel plate capacitor if both the plates are initially charged by different amount and then connected with a battery.
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0answers
40 views

Time of free fall in a repulsive force [duplicate]

The formula for time of a free falling body when acceleration is not constant can be found in any answers here at this site and also at wikipedia. But I haven't been able to find any formula for a ...
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0answers
27 views

Static field on plastic slide only during day not night

Can anyone fully explain why- A modern kids park play ground slide made of plastic has a static field of electrons gathered on it only during the day and never at night?
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2answers
173 views

The Zero Electric Potential of the “Earth”

I know its the potential differences that matter and generally we define the zero of the electric potential according to our convenience. I would like you to look at this standard problem: Charge $-...
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2answers
50 views

Calculating charge density $\rho(r)$ using Gauss law (both forms)

Below is a question given in my assignment. I tried applying Gauss law in both forms, differential and surface integral form. But both there is a difference by a factor of $2$. Is the differential ...
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0answers
16 views

The distribution of net charge in the Millikan oil drop experiment?

What is the distribution? Of course it depends on the concrete setup. But, what is the typical value? The concern is that, if the distribution is peaked at, say 1000, it would be very difficult ...
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2answers
45 views

Zero electric field in empty region of hollow conductor

A hollow conducting shell having a net charge of +Q has a point charge -Q placed at its centre. From the diagram, it looks like Suppose the radius of the inner shell from the origin is a and the ...
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0answers
30 views

Grounding system of conducting plates

So, I always make mistakes on problems such as this (the grounding part), so I'm hoping someone could really explain to me how the process works . There are n large parallel plate conductors carrying ...
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0answers
25 views

The velocity of the charged particle in the magnetic field [duplicate]

Enrico Fermi considered that moving charged particle gains energy in the magnetic field, so its velocity increases. According to the Lorentz Law $\vec F=q\vec v\times\vec B$. Work is $A=\vec F\times\...
2
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1answer
54 views

Lorentz force in different reference frames?

I have been introducing myself to special relativity and relativistic electrodynamics, and became curious about the similarity of the electric and magnetic forces. I'm trying to show that the combined ...
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1answer
41 views

Maximum electric field of a circular ring

How do you differentiate the equation for electric field of uniform ring $$ E_x = \frac{kxQ}{(x^2+r^2)^{3/2}} $$to get the maximum at a point? My book says $x = \frac{r}{\sqrt2}$. I tried ...
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Electric field of an infinite plane (with and without an infinite conductor)

Suppose we have an infinite and uniformly charged (of surface charge density $\sigma \gt 0$) plane at $z = 0$. We can find the electric field at any point $(x, y, z)$ by computing an integral all ...