The study of the presence and flow of electric charge. Charges, currents, fields, potentials.

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Electric field inside a Regular Tetragonal pyramid?

Imagine we have a Regular Tetragonal pyramid that its bases are Equilateral triangle with $a$ as the length of each of its sides. And three equal charges $q$ are put in three of its four vertices....
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1answer
14 views

Electric vs permanent magnets for alternator (turbine generator) [on hold]

Here's what I know about rotating electric generators (alternators?): they spin permanent magnets on rotor alongside stationary wire coils or vice versa (sync vs async designs) produce 1 or 3 phase ...
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22 views

Resistance increase with length because of more scattering?

I am referring to one of the answers to this old question. I can't add comment to it because I don't have enough reputation. So here I rephrase the question: does resistance increase with length ...
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15 views

How are the charges on the plates of a capacitor distributed?

Given a specific overall amount of energy a rectangular parallel plate capacitor stores what number of atoms on a specific plate would have any given specific charge?
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17 views

How much heat does a Thermoelectric generater need to produce and how much would it produce [on hold]

How much heat (Fahrenheit) does a Thermoelectric generater need to produce electricity and how much would it produce
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28 views

Transformer primary and secondary coil current problem [on hold]

A step up transformer has 300 turns on its primary coil and 90,000 turns on its secondary coil. The potential difference of the generator to which the primary circuit is attached if 60 V. The ...
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1answer
44 views

Even when the drift velocity of the electrons is very small, how is current in the circuit established immediately?

So I have this question in my textbook and Ive also got it in my test. Ive written a wrong answer. My friend wrote the drift velocities of each particle add up and he got full marks. Is it right? Can ...
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1answer
33 views

Earthing, neutral and Earth's conductivity

Ok so this is gonna be a lot of mini-questions. What exactly is the neutral wire? How does earth conduct electricity for a live AC mains even though its just dirt and stones (it should be an ...
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0answers
26 views

Electric circuits [closed]

I could not figure out why my right lateral tight thigh just above my knee was slightly was irritated in I strange way. It was not a deep pain in the muscle and it could be rubbed away but it ...
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27 views

What difference does it make if the turns in a tesla coil overlap?

Would a tesla coil in which the primary coil is made by overlapping the turns of the wire work?
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0answers
26 views

Do wires have a potential difference? Why? [closed]

I just want to know: do all conductors have potential difference? What about wires or bulbs specifically? Where does this difference lie?
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1answer
11 views

How do ink droplets passing through two charged metal plates become charged as well?

In the working mechanism of an inkjet printer, I came to know that ink droplets in the form of a stream pass through two charged parallel metal plates ( like a parallel plate capacitor) and while ...
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0answers
24 views

Strange roughness feeling on electrically ungrounded surfaces [duplicate]

When I have a device or a surface (typically metallic) that are not well connected to ground I feel a strange feeling when I pass (gently rub) my hand on them. Like the roughness of the surface is ...
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1answer
38 views

Possible reasons of electrocution in a good earthed appliance during sudden power off [closed]

I was working in a industry. When I was using a machine, I felt slight electrical shock at the exact moment when the power supply went off. The machine is properly earthed. In spite of that I got ...
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0answers
19 views

What is the Direction of flow of electricity? [closed]

I am actually confused about the flow of electrons , I had many questions regarding to this What constituted electricity ? In fact , What electricity actually is ? Does protons does not flow in ...
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0answers
32 views

Number of ions required to transmit a particular amount of charge [closed]

The question is as follows: 'If 0.035pC of charge is transferred via the movement of Al3+ ions, how many of these must have been transferred in total?' I converted the charge to coulombs (0.035x10-...
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1answer
99 views

Does Maxwells equations imply $R=const*\rho$?

Suppose we have a resistor in a strange shape, filled with a medium of resistivity $\rho$, assuming only maxwells equations apply, is it true that R is proportional to rho, even for very low ...
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1answer
16 views

Is peak voltage or peak current kept constant when we change resistance in an AC circuit?

I found online that Ohm's law still applies to an AC circuit and that $V_{peak} = RI_{peak}$. However, I can't seem to find anywhere weather an AC source will : Act as a voltage source and keep its ...
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2answers
39 views

electric current

How can positive charges flow in current? I mean , we know that there is a particle called electron which can move but there is no such positively charged particle which can flow , there can be ...
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1answer
25 views

Voltage in parallel and series connection

In series connection, voltage is said to be different and current constant across the circuit. How does it come about ? Is it due to the accumulation of electrons on one side due to resistors? Or, if ...
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1answer
19 views

Armature of electric bell [closed]

I want to know that why is the armature of the electric bell made up of soft iron ? I googled this out and everywhere it was written that it is because of its propert to aquire electromagnetism but I ...
5
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2answers
170 views

According to relativity theory, what is the force that two electrons moving radially apart exert on each other?

According to relativity theory, what is the most general expression for the force that two electrons moving radially apart exert on each other? I am looking for a function $$F(r(t)),$$ where $F$ is ...
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2answers
44 views

Uniformly charged rod electric field

A uniformly charged rod of length $L$ and total charge $Q$ lies along the $x$ axis as shown in in the figure. (Use the following as necessary: $Q$, $L$, $d$, and $k_e$.) (a) Find the components of ...
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3answers
79 views

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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1answer
33 views

What will happen if we establish a physical connection between ground and ionosphere?

https://en.wikipedia.org/wiki/Ionosphere The ionosphere is a shell of electrons and electrically charged atoms and molecules that surrounds the Earth, stretching from a height of about 50 km (31 mi) ...
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20 views

How does the velocity of a magnet falling through a solenoid affect the induced voltage?

Given Faraday's Law, $\mathcal{E}=-N \frac{\partial \phi}{\partial t}$, we can induce an EMF by dropping a magnet through a coil of wire. How would the velocity of this magnet relate to the induced ...
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1answer
35 views

Why does the primary coil get very warm with DC supply but not with ac supply?

It's about an investigation carried out on the transformer effect . The primary coil of 20 turns and the secondary coil of 50 turns is wound around a laminated iron core.
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1answer
55 views

Do any fundamental particles with gravitational or electric dipoles exist?

For magnetism: $$ \oint \vec{B} \cdot \mathrm{d} A = 0 $$ For electricity: $$ \oint \vec{E} \cdot \mathrm{d} A = \frac{Q}{\epsilon_0} $$ For gravity: $$ \oint \vec{g} \cdot \mathrm{d} A = -4\pi G ...
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3answers
21 views

Difference in directions of charge and current.?

I just dont understand that why does charge flow in a different direction as that if current when current is the rate of flow of charge.
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2answers
30 views

Why is it that for a source of emf, current flows from lower to higher potential?

I'm quite confused about this actually! In fact, I had always thought current flows from a region of higher potential to a lower one. Does it have anything to do with the fact that it's a source of ...
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1answer
48 views

Electrolysis of copper sulphate solution using platinum electrode [closed]

Please explain the electrolysis of copper sulphate solution using platinum electrodes ,and explain why copper ion was preferencially discharged rather than hydrogen ion,and also were the hydrogen came ...
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2answers
35 views

What is permittivity in free space?

From Coulomb's law, we know that epsilon-not means permittivity in free space. It's unit is C^2 N^-1 M^-2 ( coulomb sqr per newton per sqr meter). But what does it mean PHYSICALLY? For example, 1 Pa ...
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1answer
38 views

How does voltage produce current?

I am studying electric current and i dont understand how does voltage(potential difference )produce current? PS : I am a 10th grade student so please avoid complicated terminologies.
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36 views

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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2answers
21 views

Electricity and electric fields equations [closed]

Whats the difference or relationship of $q$ between the equations $E=F/q$, $v=W/Q$ and $Q =ne$ ?
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1answer
25 views

Current flow in absence of a potential difference [closed]

What if at two different points in a wire connected to a system of capacitors and resistors, the electric potential is equal. Will the current flow? There is also a battery connected.
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0answers
24 views

Self studies reagarding physics [duplicate]

Firstly, i would like to apologize for the off-subject thread,but I am in desperate need for help.I am a 12th grader at a very good high school in eastern europe ,but ,unfortunately, i didn't have the ...
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1answer
23 views

Induced current in a rectangular loop [closed]

The question is How much heat is generated in the resistor during the loop's entire path into and out of the magnetic field? Give your answer in J. I used Faraday's law and managed to get the ...
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1answer
33 views

Wind turbine impact on cars fuel consumption [closed]

I have question that I still can't resolve. How much cars fuel consumption rises(l/100km) if I attach 1 kW wind generator to cars body? How can I calculate that and what do I need to know? ...
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3answers
43 views

Ohm's law and an ideal voltmeter

In an ideal voltmeter there is infinite resistance so because of which no current is flowing through it and the voltage reading is not affected. The ohm's law stated that V = I * R In an ideal ...
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0answers
23 views

PARALLEL COMBINATION OF SUPERCONDUCTORS AND RESISTORS [duplicate]

........................please reply to the question above in the picture. I have tried a lot and have thought about it for a long time. Please help me and answer in simple words. AND I REQUEST NOT ...
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1answer
59 views

Power generation with a long, horizontal pipe, using atmospheric pressure differences

Straight to the point. If I float a pipe starting from a point in the ocean that has the atmospheric pressure of 101 kPa (Call it Point A) all the way to another geographic position on the ocean with ...
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0answers
30 views

Dynamic energy of capacitors in circuit

If I have 3 capacitors and 1 battery in a circuit how should I connect them in order to have maximum dynamic energy, when I connect them with the battery? Parallel or in series?
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1answer
37 views

Electric field inside an insulator's cavity [closed]

I'm trying to find the electric field inside insulating sphere's cavity, and I don't know how. However, if there was an conductor I'd know that $E=0$ from Gauss's Law.
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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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1answer
28 views

Electricity Transformers and power

Since Power = V*I increasing voltage reduces current and so it is better to have a higher voltage. My question is, since voltage is potential difference i.e. joules per metre, increasing the voltage ...
26
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7answers
3k views

Why are the electric force and magnetic force classified as electromagnetism?

I confuse the four kinds of fundamental interactions, so I think the electric force and magnetic force should not be classified as a big class called electromagnetism. Here is my evidence: The ...
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2answers
65 views

Electrocuted at Parking Pay Station After Snorkeling [closed]

This is my first time posting here so bear with me. Also, the circumstances are strange so I am posting quite a bit of detail because I don't know what is relevant and what is not. The short story is ...
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1answer
50 views

Why is the average thermal velocity 0?

Thermal velocity is the velocity of the free electron due to their random motion. So how is the average value 0?