Questions tagged [electricity]
The study of the presence and flow of electric charge. Charges, currents, fields, potentials.
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How current flows in an ideal wire? [duplicate]
what are the assumptions that we make, that should be kept in mind when a current is flowing through an ideal wire of 0 resistance? And what is the speed of the electrons in an ideal wire? if I have a ...
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Why doesn't voltage increase when the wire length increases; there's more work to be done?
This Q&A did not answer my question.
The voltage of a circuit is the difference in each Coulombs potential energy at the negative pole, compared to the positive pole. At the negative pole, there's ...
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Power and Solar Energy
If power cannot go both ways at the same time through a wire, how do solar panels feed back to an electrical grid?
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Principle of electromagnetic induction
In question, it is explicitly mentioned that the coil is placed in the uniform magnetic.
When the coil is not in the magnetic field, the current flowing through the coil is zero; hence the change of ...
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Potential Divider Circuits
Consider the following circuit:
From my understanding, consider the series circuit without the $V_o$ part. The voltage must be used between resistors $R_1$and $R_2$. We know $V=IR$ from ohms law. As ...
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Why small particles are attracted by charged objects?
Everyone knows this experiment: You mix salt and pepper and use a charged balloon to separate the pepper from the salt.
I never really understood how this works. In school (long time ago) we learned ...
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Why chemical energy is doing the work on the electrons to move them from cathode to anode and not some kind of force?
We say that in an electrolytic cell the redox reactions occuring on the electrodes are exothermic and that chemical energy does work on electrons to move them from cathode to anode and this work done ...
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Why do electrons not remain at higher energy levels?
I am beginning to learn some very basic electronics. I was learning how and why lightbulbs light up. It turns out it happens because they have a very thin filament which makes the passage very narrow ...
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Ideal Superconductor connected to Zero Voltage
If an ideal superconductor was just left alone, with no potential difference, what would be the current flowing in it?
According to Ohm's Law, $V = IR$
Hence, if a superconductor of $0\Omega$ ...
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Electricity through water
If you're sat in a body of water through with an electric current runs, can you survive if you create an earth wire to lead the electricity away from you?
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Charged particles accelerating toward one another gain both kinetic and potential energy
If we have two particles (let's just say of equal but opposite charges, $-q$ and $q$) and place them a distance $r$ apart, the potential energy of the system is:
$$
U = k \frac{q^2}{r}
$$
Now if we ...
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Why Faraday homopolar generator need brushes?
It is said that if one would attach a load physically to the rotating disc from center to rim no current would flow because both in the load wires and the disc itself currents would be generated in ...
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Why electric currents in equal and opposite direction cancel each other?
I know that electric current is a scalar quantity and hence it should not follow vector addition. But I have read that equal currents in opposite directions will cancel out each other so is this kind ...
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Flow of electricity using two charged balls
Let us take a positively charged ball and a negatively charged ball and join them with a metal rod. Now if we connect one end of a wire with the positively charged one and the other end of the wire ...
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How can Electricity travel at the speed of light?
If electricity is the flow of electrons, how come it can flow at the speed of light? Shouldn't how fast it moves be limited to a speed lower than the speed of light because it has mass?
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Translation of Cabeo's Philosophia magnetica
Is there a translation of Niccolò Cabeo's work Philosophia magnetica into English (or other modern language)? The original text in Latin is available for example here but I can't find any translation (...
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Using the electrolysis of water to cool a room [closed]
Browsing the internet today I came across this very esoteric paper which purports to describe the construction of a device which uses the electrolysis of water into hydrogen and oxygen (a highly ...
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Electric flux through a square surface by a charge kept above it [closed]
A charge $q$ is placed at shown at a height $a$ above the center of a square surface of side length $a$. I have to find the flux due to $q$ through the surface.
I do not find any symmetric shape about ...
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Why electric charge does not gain net energy in closed circuit?
In a text book, when they calculate power dissipated in a closed circuit, they use circuit with a battery and one resistor. Idealized positive charge travels from +...
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Does a bulb glow brighter if kept closer to the battery?
If the surface charges propagate an electric field to cause the electrons around the bulb in the wire flow(which is why it will light up even if the circuit is as long as 3*10^8 km, if the battery and ...
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Does the physical shape of a current carrying conductor affect the shape of its magnetic field?
I am wondering if the physical shape of a current carrying conductor will have any effect on the shape of its magnetic field or is it that the magnetic field surrounding any current carrying conductor ...
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Is Net force per unit charge zero in a conductor in the presence of a magnetic field?
Let's assume there is a perfect conductor. This conductor starts moving with a constant velocity in the presence of an external electric field and magnetic field.
Generally an external magnetic field ...
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Heating Effect of Current wrt Transformers
I just learnt that we use step up transformers to reduce heating losses in overhead wires. I was given some values.
Say, the power plant is a 1 million watt rated plant.
The voltage is $400V$ at the ...
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How could one measure the capacity of a battery with one instantaneous meter reading?
My car battery when fully charged operated the car lights and air conditioning for a few minutes (without the engine being on) before it was not powerful enough to operate the starter motor.
The ...
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(A10) If light is an EM wave, can it interfere with electrons in a live wire, leading to a change in the wire's current?
Here's my question: If light is an electro-magnetic wave, with oscillating magnetic and electric fields, wouldn't light interfere with the free electrons flowing (slowly) in a wire, as the electric ...
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Isn't heating insulator enough for sufficient electrons to escape valence band and conduct electricity?
Diamond has about 5.5eV of energy gap, So If I heat diamond it will get atleast 1J energy which is enough to excite about 10^18 electrons, But Diamond still not conduct electricity, Why?
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Passing electricity through magnets [duplicate]
Looking to link up with someone who has experience with electricity and magnets. I’m wondering if you can pass electricity through magnets similar to a wire.
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Why aren't "composite" capacitors a thing?
Recently I started researching more about capacitors and I wondered why it's not possible to put a layer with a high electric breakdown strength between two layers of high permittivity? Wouldn't you ...
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How many typical nuclear power plants does it take to power 1 billion typical cellphones per year? [closed]
Not asking for an exact answer clearly.
Let us say that a cellphone user typically watch like 2 hours of video per day and it is say on an iPhone of your choice.
How much power would be needed to ...
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Why doesn't the coil of a DC motor accelerate infinitely?
In a DC motor, when current is passed through the coil in a DC upon contact with the brush, it seems to be moving at a constant speed. But after half a rotation, a current is passed through the coil ...
