Questions tagged [electricity]

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

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How Does Voltmeter Actually Work?

I've tried to find a specific answer to my question, but couldn't. My question is why Voltmeter Shows Zero Volts, when we connect the leads not across a resistor (or any other component) but side by ...
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How does the act of bringing poles closer together increase electromagnetic strength?

According to my textbook, the strength of a horseshoe electromagnet can be increased in the following ways: Increasing the amount of current flowing Increasing the number of turns of the coil ...
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Is also second wire in power plant ( from alternator for example) also connected to ground? [closed]

If one wire from AC supply is "hot" and goes to one end of power plug (let's keep it simple) and second end of power plug is neutral a goes to ground in "power plant", than also ...
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Please help me understand the nature of electricity and particle behavior

I am trying to understand how electricity works on quantum level. Precisely how is energy actually transferred from generator to the consumer. Here is what I managed to understand so far by reading ...
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The Concept of Parallel Resistors

If the equivalent resistance of resistors in parallel is lower than all resistors, does this mean each resistor is resisting less than its maximum (what is written on its label)? I am trying to ...
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Sodium battery generating heat and electricity?

Do there exist batteries with a porous membrane between water and solid sodium generating heat that is transformed to electricity by a thermoelectric element? Are there studies on that?
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Resistance And Electric Power

In a practice problem A motor rated at 20 A with a voltage of 115V exerts a force of 4900 N over a distance of 10 m in 30 s. Using the formulas $P=VI$ and $P=\frac{Fs}{t}$, we can see that the motor ...
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Where does the drift current in a pn juntion come from?

I know I know. There are around 4 similar questions on here, but they do not properly answer my question. I'd like to know where the drift current in a pn juntion (no bias) comes from. From what ...
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How do devices control how much power they use?

In power systems (Australian for reference) the grids run at a constant voltage of 220V. I’ve heard of switches were less voltage being used is created by adding more resistors for example to dim ...
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Coulomb's law in medium

As we know that when we replace vacuum by some medium between two point electric charges then the force between them becomes 1/K times the initial value, where K is the dielectric constant of medium. ...
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Is there a way to measure individual parts of an electric field from only one part of it?

Let's say I have an electric field made up of charges, and let's say I have the ability to measure a single electron's charge/spin (either positive of negative). Is there a way that you can measure ...
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Why did the defected bulb glow brighter when switched off?

Suddenly an LED bulb in my house stopped glowing (actually it was having very little brightness (can be noticed in the video)). But when I switched off the bulb , it first glows brighter and then ...
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Are Idealized Transformers Realizable?

Since parasitic capacitance in an inductor is always in parallel with its inductance, would this effectively become analogous to magnetic remanence exhibited within rebars (made from carbon steel) ...
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Accumulation of charge and potential difference across a resistor

If there is no accumulation of charge across a resistor, how can a potential difference (that is, potential drop) be created across it?
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If ions are stable, then why does a battery have an expiration date?

I am talking about non-rechargable batteries. As far as I understand, ions in a battery are stable form of atoms, just having excess electrons, or lesser electrons (relative to the neutral atom). Now ...
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Power conversion to temperature

When an electrical shortcut happens at a wire, the wire heat up to melting point example Is there a formula to calculate temperature reached?
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An AC ammeter is used to measure current in a circuit. The reading of the ammeter if DC and AC flow through it simultaneously is? [duplicate]

An AC ammeter reads $i_1$ when an AC current passes through it and $i_2$ when DC current passes through it. We know that the ammeter measures the RMS value in case of the AC current, i.e the The RMS ...
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Gauss's Law Application for Finding the Electric Field of a System with 2 (or more) Charges

Suppose that there is a charge configuration of 2 point charges, say an electric dipole. Gauss's Law wouldn't be so useful (but it would be possible, as far as I understand) because there is not a ...
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Why is the brightness of a light bulb dependant on power?

If: Temperature is a measure of the average (kinetic) energy of the particles which make up some material Power is measure of energy transferred per second (J/s) The temperature of the filament in a ...
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Does current density from a wire same in smaller cross section?

To be more simple, If current $i$ is flowing through a long cylindrical wire does the current density of region $A$ and $B$ same?
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Does making a conductor spiky increase its capacitance?

I'm thinking of the proofs for "charge accumulation at the points of a spiky conductor" e.g. https://www.feynmanlectures.caltech.edu/II_06.html 6-11 If charge accumulates at sharp edges, I'm ...
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Confusion with Electrostatic Potential Difference

Suppose that you have a positively charged plate at a plane (xy-plane, for example). Therefore this plate exerts an electric field with a magnitude of σ/2ε₀. Due to this, there will be the same ...
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Earthing vs grounding

In some websites they say there is a difference between Earthing and grounding but some of them say they don't.Is there any difference between "Earthing" and "grounding"?
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Electricity in battery through Galvanic Cell

I found out how galvanic cell works and it was very interesting to know. But when I m reading electricity and current mechanism in physics, the book says that the electrons through oxidation (Zn lose ...
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What force moves electrons through a conductor that is rotating in a magnetic field [closed]

Is it the magnetic force ( F= qv +B ) or the electromagnetic force (F= q(E+vxB) that acts on the electrons of a conductor that is moving in a magnetic field? Thanks.
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Is it possible to generate electricity using only permanent magnets?

EDIT: I'm talking about generating electricity using only the magnets with no additional energy input. I'm sure the answer is no, but can you explain why it's not possible? Does it violate the law of ...
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Potential difference across two points in a current-carrying wire [duplicate]

I have had this doubt for quite a while and I have tried reading answers to similar questions but I'm still not sure. If I connect a voltmeter at A and B, what would be the reading? Is it going to be ...
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101 views

Can positrons be used like electrons to create electricity? How does electricity even work?

In galvanic cells, electrons are used as the source of charge difference. This creates a current that we can use for a large variety of purposes (i.e. light up a bulb). When I think about this ...
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How are bound charges in a dielectric "in equilibrium"?

In Griffiths E&M, he provides two equations with regard to the energy of a system. The first being \begin{equation}\label{eq:1} W = \frac{\epsilon_0}{2}\int\limits_{\text{all space}} E^2 \ \...
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What happens to the inductor voltage if the inductor is disconnected from the LC circuit exactly when its energy is zero

In this thought experiment we consider the tank circuit, where the energy is exchanged between the capacitor and inductor. The energy when stored in the capacitor is $E_C = \frac{1}{2} \cdot C \cdot ...
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Why doesn't lightning stop when it starts raining?

According to my understanding, lightning happens because the clouds get charged due to friction from the moving clouds and the ground gets polarized by the nearby charged clouds. And the two opposite ...
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How to calculate Potential Difference between 2 random points in a circuit? [closed]

This might be a very easy question to solve for a lot of you but I was having an extremely hard time evaluating the potential difference between points A and B. Thats why I decided to just post this ...
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Equivalent Resistance in arbitrary situation [duplicate]

Find the equivalent resistance between points A and B. I tried to connect a battery of emf $E$, drew a current $I$ from it, and formed equations and variables but was unable to solve them. Please ...
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Do pollen grains really act like a dipole?

Yesterday I was solving some electric field from resnik book and one of the solutions assumed a bee to be a sphere of charge $60 \;\text{pC}$ and the grain which sticks to it as a dipole due to ...
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Why is high voltage more deadly than low voltage?

Why is higher voltage said to be more dangerous? Doesn't higher voltage decrease current as P = IV where P is constant, thus making it less deadly?
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Electricity supply in homes is AC but what about rms value that has only one direction? [closed]

In our homes, electricity supply is AC.but we have rms value in our homes...How do they relate? Is rms value generated in transformer or what??
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On a nanoscopic level, what really happens to the electrons in the secondary coil of a step-up transformer?

I know that when AC is passed through the primary coil of a step-up transformer a higher emf is induced in the secondary coil (with more turns) of the transformer. Since energy is conserved, and P = ...
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Does a 1m2 solar panel really provide more power than 1l/s of water falling 1m?

I'm trying to develop an intuition for small scale power, in the context of off-grid power. Are these sums correct? A 10% efficient solar panel, of one square meter, with incident 1kW sunlight, will ...
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Current in a cylinder moving with uniform velocity

This question might seem silly. I solved this question in the following way. Although, The answer I got from this method is correct but I still have a conceptual doubt in my solution. I have put $\...
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How can electrons realize that there is a path of zero resistance to move? [duplicate]

In this situation if we apply voltage across the terminals of the circuit, we will see that no current passes through the resistances R1, R2, R3 rather all the current passes through the wire of zero ...
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Lightning's tendency to find a tall point on the ground

Is lightning's tendency to connect to a high point on the ground due to probability in the colloquial sense, or is there some sort of electromagnetic stream of "information" exchanged ...
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Is carbonated water more conductive than salt water or baking soda-water mix?

Sorry for this entry level question, I'm an amateur, and I was wondering about alternative water mixtures for electrolysis. My question is: Does carbonated water have better conductivity for ...
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Does waterglass conduct electricity?

I'm wondering if waterglass (sodium silicate) either in solution and/or dry conducts electricity?
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Could you electrically charge a liquid or granules to refuel EVs with it?

Is there a physical law that would make an electrically charged liquid or granules impossible to produce? Theoretically it should be possible to refuel an EV by adding two different liquids to it in ...
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Electromagnetic induction with a two-magnet assembly

I performed a bunch of experiments where I let a two-magnet assembly free fall through a vertical solenoid. The magnets are shaped like rings, are identical in size, and are held in place - with a ...
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How do dryer sheets work?

For what I can understand they absorb the static electricity of clothes but how? I'm confused because I thought that to neutralise a charge you would need to have the equal opposite charge and make ...
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If you add more coils around a spinning magnet does it produce more electricity?

If you have a magnet spinning at 1800RPM and put multiple coils next to it does it produce more electricity than if you only put one coil next to it? Will more coils require more energy input to keep ...
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Capacitors and Kirchoff's Voltage Law

If we connect capacitor to voltage source, its voltage will be equal to voltage of the source when capacitor is fully charged due to Kirchoff's voltage law and no current will flow in a circuit any ...
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Formula for Temperature Gradient due to Joule Heating [closed]

I was wondering how to calculate how much the temperature will increase in a cylindrical wire due to current passing through it, I did some googling didn't find anything so I came up with the ...

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