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

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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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87 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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29 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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38 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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62 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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25 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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33 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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74 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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42 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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40 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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37 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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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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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
55 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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1answer
63 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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33 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
42 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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14 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 ...
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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
67 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
56 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?
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1answer
28 views

Difference between energy loss at high voltage and high current

When reading about power transmission one very common statement is that power is transmitted at high voltage to minimize loss in the form of heat. What confuses me is the governing equation. Aren't $...
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1answer
46 views

Resistivity - Resistance of a wire wounded closely together

Here is the question I'm facing, The cross sectional area of a bare wire is a square of area 1.00mm^2. A 10.0m, length of this wire is wound close together on a wooden cylinder so that neighbouring ...
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1answer
79 views

No photoelectron is emitted from which of the following metals?

So there was this multiple choice question in an exercise in a bookI'm reading. I know that the forum is about discussions. But I want to know what the answer to the question is and why it is so. ...
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24 views

May the total charge in a supercapacitor be different using unipolar and bipolar voltage power supply?

Consider a supercapacitor where a Helmoltz double layer is formed at each of the 2 electrodes, which is like having 2 capacitors mounted in series, but with different polarities. The total charge at ...
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2answers
69 views

Which part of my idea is wrong about infinite energy produced by EMF for certain circumstance?

As a someone who is on the first year of EEE student, facts in a simple way: time varying magnetic fields around conductors produce electricity for outer space, object will keep going at the same ...
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0answers
18 views

Negative torque by an alternator during sudden change of load

I have often watched that when generators are started and suddenly when the load is increased, there is a drastic change in the RPM of the engine before it stablizes. From this it becomes clear that ...
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2answers
782 views

Does A.C. make the material through which it is flowing vibrate?

So recently I have been studying A.C. circuits and the graphs show that the current oscillates itself as a function of time. Now, according to me an oscillating body vibrates. Hence, the oscillating ...
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69 views

electrical field in coaxial cable

When getting the electric field between the outer and inner cylinder. why is it that we are only concerned with the field generated by the positive charge distribution on the inner surface and not ...
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1answer
56 views

Magnetic force on a charged particle doesn't affect total energy

So there's this sentence in a book I am reading. It states "When a charged particle is placed within a magnetic field, despite the magnetic force acting on the particle, there will be no change in the ...
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43 views

Principle of capacitor

It is said that second conductor reduces the potential of fist conductor and hence increases charge taking ability of first conductor My confusion... As per my limited knowledge it is electric field ...
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24 views

The Electric Grid: if AC load/generation causes frequency to change, what happens in a DC circuit where there is no frequency?

I've been trying to understand why, in the AC electric grid, frequency changes when there is imbalance in load and generation. Why doesn't voltage, or current, or power factor change? Why does ...
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1answer
26 views

Power current Electicity [closed]

When A 500 W electric bulb and 500 W heater operates at their rated voltages,the filament of the bulb reaches a higher temperature than the filament of the heater.The most important reason for this is ...
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1answer
80 views

What causes the buzzing sound when the electricity changes into heat?

When I turn on any kind of electric heating (kettle, cooker, heater, ...), it keeps producing a constant buzzing sound. What is the exact cause of that sound? Do the electrons of the electric ...
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1answer
58 views

How commutators reverse the direction of current?

I've seen this video and read this article about commutators but I still couldn't get how commutators reverse the direction of current.I would like an simple and intuitive answer.
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1answer
53 views

Flow of charge through metal wire [closed]

It is the flow of charge that matters -- electrical current is defined as the flow of charge. " -person W [...] if the flow of charge is all that matters; and electrons with their charge attached ...
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2answers
39 views

Why do people say that 'power flows' into or out of a component in an electric circuit?

Currently, I am learning about electric circuits, and how to apply the basic concepts of physics, like work and energy. But I keep running into the same phrase--on Wikipedia, my textbooks, everywhere--...
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1answer
81 views

What do the batteries actually do to the electrons?

I am plagued by this simple question that what force exactly causes the motion of an electron in the middle of a lattice of electrons of a wire? a. Is it an electric field created inside a wire due to ...
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3answers
392 views

What will happen to a man if he hangs from the power cable of train using one hand and secondly using two hands? [duplicate]

If a man holds and hangs from the power cable of trains with one hand, will he be alive or will he die if he holds and hangs from the electric wire using two hands without touching the ground ? I ...
3
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2answers
88 views

Why do some people support more electricity than others?

There is a game where people hold by their hands and two of them touch the electrodes of a shock box, then an electric current flows through them. I understand that since they are all making a single ...
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141 views

Why does internal resistance increase as current decreases?

Our class conducted and experiment to investigate internal resistance and terminal pd, using a cell, fixed resistor and variable resistor. The results were as follows: As the resistance of the ...
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1answer
106 views

Is Phone-Charging Plant Product Even Possible?

Bioo, a new company making the rounds in the press, claims to produce "electricity from plants' photosynthesis." Specifically, their website claims that a single potted plant with their integrated ...
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8answers
2k views

Why is capacitance defined as charge divided by voltage?

I understand that capacitance is the ability of a body to store an electrical charge and the formula is $C=\frac{Q}{V}$. What I don't understand, however, is why it is defined as coulomb per volt. Of ...
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2answers
76 views

How do we get 25kV at power stations? [closed]

Could anyone tell how we get a potential difference of 25000v at power stations? Is it due to the number of electrons present or the speed of the turbine or the large induced emf generated by the ...
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1answer
31 views

Why there cannot be induction current between plates of capacitor while discharging?

If a capacitor gets charged by induction through the plates, then why there is no induction current between them while discharging instead of displacement current ?
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54 views

What is the difference between the potential difference and potential energy of an electron?

What is the difference between the potential difference and potential energy of an electron? Let's take an example the potential difference (PD) across a resistor. if there's a current flowing, the ...