For questions that utilize the concept of electric fields (commonly denoted by the letter E), or for questions whose answers likely involve electric fields. More specific than the [tag:electricity], as questions about the phenomenon & theory of electricity do not necessarily involve the discussion ...

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39 views

Why is voltage input different from voltage output in a circuit?

This is more specifically, when performing the meter bridge experiment. The meter bridge experiment is an experiment in which using the meter bridge, a jockey, voltmeter, battery eliminator, you keep ...
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1answer
511 views

Can the electric field strength of a wire simply be calculated using the voltage / length formula?

Can the electric field strength of a wire simply be calculated using the voltage / length formula: Electric Field Strength = Voltage Across Wire/ Length of Wire I am asking about a wire with current ...
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1answer
38 views

Finding electric field of a line charge [closed]

I have a bit of an issue setting up the integral for finding an electric field of a particular scenario. The scenario is that a line charge of length R is a distance R from the left side of the ...
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0answers
44 views

Could a 1kHz EM field be detectably disturbed by an action potential?

This might be completely off base, but I'm wondering if this would be possible. Neurons fire action potentials that can be modeled as low-intensity (~100mV) EM pulses of 1kHz frequency (up and back ...
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1answer
94 views

Why isn't the electric field just a mathematical tool?

I'm limiting my question to this field because it is the only one I know of with a certain degree of knowledge. I doubt they really exist because of the following reasoning: Coulombs law was stated ...
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0answers
30 views

Determining if an object is dielectric or metallic

In a worksheet I was given, I had to find the net electric field of P which is L distance away from a bar. The last question is ...
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0answers
64 views

Can we use EEG to record signal from spinal cord?

My hype is about the idea that Spinal cord around neck is the place every signal sent to control whole body. So if we can record all signal, we could analyze movement of our body from finger to leg ...
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2answers
873 views

Gauss Theorem:Electric field of an uniformly charged non-conducting spherical shell

I want to know the electric field of an uniformly charged non-conducting spherical shell. I know that in case of conductors(metals),the sphere can be shell or it can be solid,but in both the cases ...
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2answers
111 views

Draw the charge configuration according to the electric field [closed]

I'm trying to draw the charge configuration outside the regions that lead to the given electric field patterns. Can someone show me how?
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5answers
4k views

How is it possible to accelerate a neutron?

It is possible to accelerate a charged particle in an electric field, how is it possible to accelerate a neutron? How can we control its velocity?
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1answer
131 views

Why don't neutral atoms distort the electric field?

Suppose I have a positively charged conductor with a cavity. There's a positive charge inside the cavity and the system has reached electrostatic equilibrium. Then there's negative charge surrounding ...
3
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2answers
820 views

Physical meaning of imaginary part of Electric field?

As far as I know (or I thought I knew), if we have an electric field $$\mathbf{E}=\mathbf{E_0}\cos(\omega t - kx),$$ we can define it as the real part of $$\mathbf{E}=Re(\mathbf{E_0}e^{i(\omega t - ...
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2answers
797 views

What is the difference between electric charge and electric flux?

What is the difference between electric charge and electric flux? According to my knowledge electric flux is nothing but electric charge enclosed by the closed surface.
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3answers
141 views

Vector decomposition validity

Is force or field decomposition into component vectors always valid? Lets say a constant electric field $\vec{F}$ is acting in space such that it makes an angle $\phi$ with respect to the horizontal ...
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1answer
47 views

Electric Field of a sphere

Is there a point in space where the electric field is half of the electric field on the surface of the sphere? I just got curious if it would be possible.
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1answer
138 views

How is electric field strength related to potential difference?

I was looking at the derivation of drift velocity of free electrons in a conductor in terms of relaxation time of electrons. Here a metallic conductor XY of length $\ell$ is considered and having ...
3
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1answer
113 views

Definition of a field line?

Ok so I finished by A-levels last year (english exams 18 year olds take) and we defined in my physics course we defined field lines (for an electric field) as: The path a free positive test charge ...
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2answers
56 views

Direction of current in concentric cylinders

Example 7.2 in David Griffiths E & M book (3rd edition) has a side view of 2 concentric cylinders, with smaller radius $a$ and larger radius $b$. The region in between $a$ and $b$ has ...
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1answer
57 views

How to find whether the electric field between capacitor plates is above or below the electrical breakdown limit of the insulator between the plates?

Let's say the two plates of a capacitor have charges $q_1$ and $q_2$. The separation between these plates is $d$. I know that I can calculate the electric field by dividing the voltage that is applied ...
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1answer
46 views

The difference between EMR and lone Electric and Magnetic fields

I fail to understand the true difference between EMR and electric and magnetic fields. When current flows, there is an electric field due to the electron flow and a magnetic field, however no EMR ...
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1answer
135 views

How does electric field intensity look like along a wire which has one end connected to an AC source and the other one is left free?

How does the electric field intensity look like along a wire with constant conductivity which has one end connected to an AC source and the other one is left free? I mean is the electric field the ...
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1answer
694 views

Electric field strength at the center of an equilateral triangle

Questions: Three $x$ m long rods form an equilateral triangle. Two of the rods are charged to $+q$ C and the third to $-q$ C. What is the electric field strength at the center of an equilateral ...
2
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1answer
68 views

Proving the equivalency of the potential energy of a system of charges and the work required to assemble a system of charges

This is a very cool, and highly beneficial problem in my opinion. I feel as though truly understanding this proof would broaden anyone's conceptual understanding of electric potential. My textbook ...
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0answers
80 views

Sign error in calculating the electric field of point charge

I have to determine the electric field of a point charge, I get a true result except for a sign. Here is my passages. $$\nabla \cdot e = \frac{\rho}{\epsilon}$$ $$e = - \nabla u$$ $$\nabla^2 u = - ...
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1answer
50 views

Uniformly charged sphere's electric field

I am facing this topic for the umpteenth time in my college career and, of course, every teacher has explained it in a different way. In this course, to find the expression of the electric field of a ...
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1answer
209 views

What factors cause the velocity saturation to occur at different electric fields for different materials?

In semiconductors the velocity of carriers gets saturated after a certain value of electric field. In silicon it occurs at around $10^4 kV/cm$ and in GaAs at some other value. What factors are ...
4
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1answer
397 views

Why are atomic quadrupole moments calculated using nuclear spin?

It's my understanding that electric quadrupoles interact with the gradient of an electric field, and I understand roughly how this works. I am trying to calculate the interaction between an atomic ...
2
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1answer
240 views

Electric Field-Drift Velocity

Why is the net velocity of electrons (drift velocity) considered to be zero, before setting up any electric field? I mean in the derivation of the equation drift velocity: $$ v =-\frac{Eet}{m} $$
3
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0answers
96 views

Partition function of classical quadrupole in an electric field

The partition function of a dipole in an electric field is a well-known problem, analytical solvable (nice integral, can be calculated with pen and paper), for example in the Langevin treatment of ...
16
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2answers
1k views

Why is there no Gravitational Magnetic Field?

We think that the electric field and gravitational field operate similarly with their corresponding charges/masses. With just a difference that the electric field is sometimes attractive and sometimes ...
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1answer
239 views

Calculating equipotential lines and current density in a rectangular conductor

(This isn't homework, I'm trying to make an illustration for an article I'm writing.) Let's say that I have a thin rectangular bar of uniform conductivity, and I have point probes at various places: ...
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2answers
206 views

Why isn't resistance proportional to distance squared

Here we have a wire. At both ends there is an equal and opposite field caused by a chemical reaction. So, if we decrease or increase the distance between the two points, the strength of the field ...
2
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1answer
130 views

Why is an electric and magnetic field present in all universe?

the Earth has its fields due to the motion of molten metals in the core but how does this whole universe has its fields without any discontinuity? And we can say for sure that fields are present in ...
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2answers
213 views

Experiments which show the phenomenon of closed electric field lines

In german physics introductory texts often the following experiment is cited which "shows" that a changing magnetic field can induce an electric field with has closed field lines. Here is a picture of ...
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3answers
497 views

Why the electric field $\vec{E}$ is constant (=position independent) for an infinite 2D sheet of constant charge?

So I'm reading a text on electricity and it talks about using the integral to compute the total charge of a collection of points, which I mostly understand. But then we get to finding the electric ...
3
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1answer
106 views

Are electric field lines due to Faradays law closed?

Are the field lines of electric field produced by Faraday's law of induction (and assuming $\rho = 0$) necessarily closed? If not what would be a counterexample. If it's true, how to prove it in ...
4
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3answers
1k views

How does a magnetic field cause objects to move?

I understand electricity and magnetism and the relationship between them. What I never understood, and never actually seen explained in any book or website, is how opposite magnetic fields cause ...
4
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5answers
1k views

Why is the electric field of an infinite insulated plane of charge perpendicular to the plane?

I'm studying Gauss' Law, and I came across a section where we're supposed to find the electric field of various shapes (like an infinite line of charges, etc), and for an infinite plane with a uniform ...
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0answers
47 views

Electric dipole moment(EDM) underlying physics [duplicate]

I read in a physics today paper, The electron can have nonvanishing EDM only if nature violates symmetry under time reversal (T) and under the combined operations of charge conjugation (C), which ...
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2answers
160 views

Ion Optics: Electric and Magnetic field. A comparison with Light Optics

When we compare ion optics with light optics, normally we consider electric field. For example Snell's law. $n_1\sin\theta_1$=$n_2\sin\theta_2$. When an electron move from one electric potential to ...
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2answers
98 views

Weird Kinematics Homework [closed]

Here's another "hard" homework question I was given on how printers work. (I find it more confusing than it is hard.) I'm supposed to find the horizontal velocity of a charged droplet as it leaves ...
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2answers
162 views

Why is work in a constant electric field equal to the force times distance?

Let's say, for example, that an infinite plate generates a constant electric field that exerts a force of 6N on a 1C charge. To move the charge from a distance of 5m to 1m from the plate, the work ...
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2answers
75 views

Charge inside a sphere

Suppose I have a sphere of radius $r$ with all the charge residing on the surface, distributed uniformly i.e. charge density $\sigma$ is constant. I want to find the electric field created by this ...
2
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1answer
190 views

Finding the electric field around an electric eel

I'm having problems solving for the electric field and the current that an electric eel generates. Would I use Gauss's law and treat it as a long charged wire? How would I find the charge of the ...
12
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2answers
972 views

What is the nature of electric field? is it quantized? is it a wave?

What I seek here is to understand whether the electric field in its pure form as in between the electron and the proton is uniform or does it have some kind of wave/particle nature or both, does it ...
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2answers
114 views

Gauss's Law for a Uniformly Charged Solid Sphere [duplicate]

We want to calculate $\vec{E}$ at a distance $r$ from the center $O$ of a spherical polar coordinate system. Let the point on the Gaussian surface at which we want to calculate $\vec{E}$ is ...
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1answer
123 views

Upper limit to electric charge confinement?

The following questions are not intended for conventional capacitors (which stores excess charge on the outside surface), rather a type of hypothetical capacitor which is designed to confine charge by ...
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1answer
98 views

Finding the direction of the electric field of several charges? [closed]

A clock has negative charges -q, -2q, -3q,...., -12q fixed at a the position of the corresponding numerals on the dial. The clock hands do not disturb the electric net electric field due to pont ...
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0answers
45 views

What would happen if…? (Scenarios involving a ball in an electric field) [closed]

First I shall define two table tennis balls: Ball $A$ is coated with a conducting material and ball $B$ is an insulator. Then I'll define two scenarios: Scenario $I$ is a ball held from a ...
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1answer
72 views

Finding V in a electric field? [closed]

How will we find $V_{ab}$ when $\vec E = (2i+3j+4k)$ N/C , $\vec R_a = (i-2j+k)$ m and $\vec R_b = (2i+j-2k)$ m ? I know $\vec E= -\frac{d V}{d\vec r}$, but I don't know what should be my initial ...