Questions tagged [electricity]

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

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14 views

Determine the change of charge in both capacitors

I have the following circuit The switch has been open for a long time, and both capacitors are fully charged. After that, the switch is closed and the circuit is broken. I need to determine the ...
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Can electrical conductivity be made anisotropic by geometry (similar to fluids)?

Some basics about the flow of electrical current are often compared to the flow of fluids. In many cases this is quite a good model, for more in depth theory the model begins to fall apart. When I ...
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Does electrons moving from a region of higher concentration to a region of lower concentration carry energy?

So I wanted to say that in the picture given below electrons move from a region of higher concentration to a region of lower concentration, so due to that they didn't needed any external energy supply ...
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Why is there a little fluctuation when the electricity connects or disconnects?

When the electricity connects (or disconnects), if you look at a light bulb,it would first get on (off), then off (on) and finally get on (off). What is the reason for this? I heard that it is because ...
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Determining impedance of the circuit from peak values of current and voltage

Does the following equation given in my book $$i_m = \frac{V_m}{Z}$$ where $i_m$ and $V_m$ are peak values of current and total voltage $V_m = \sqrt{(V_L-V_C)^2+V_R^2}$ and $Z$ is impedance, hold for ...
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Charging a single plate of a capacitor does not work

I charged a 100nF capacitor with 12V with a battery, then i disconnect the battery from the capacitor and connect the positive side of the capacitor to ground (which is an electron source) ...
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physics question [closed]

A copper wire is wrapped 65 times around an unknown core of length $28 \;\text{cm}$. The current in the wire is $800 \;\text{mA}$ and the magnetic field due to the electromagnet is $1.63 \times 10^{-2}...
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I need to know whether these videos are fake or not [closed]

video 1 - https://youtu.be/4CiJKk5kWTo video 2 - https://youtu.be/a0sRo4ew5qA These videos are pretty convincing, but from the physics point of view... idk
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Different live and neutral wire terminals on different plugs [closed]

Here is the problem, one of the power cable(1st pic) came with XPG core reactor power supply for my computer, and the other UK plug(2nd pic) is of my Samsung LCD. And as you people can see, both have ...
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What's the magnetic field produced by a current carrying circular loop at a point on its plane?

How do I find the magnetic field in this case? I already know about the magnetic field produced by a current carrying loop at an axial point or center but what about the point on its plane?
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Do neutral conductors be attracted to a Van de Graff generator?

As far as I know, static electricity occurs when we have one object becoming positively charged, and another negatively charged, due to contact between them (usually rubbing). Those objects will than ...
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Is there any way to experimentally determine the permittivity of an object?

I want to determine the effect of temperature on permittivity, but I have not yet found a reliable method to calculate the permittivity of an object, say water. Is there any way I can do this?
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What is meant by a potential of an object in context of electricity?

On my journey on learning about electricity and voltage in particular, I asked a few questions in this site. And I often come across terminology of relating potential to objects, like for example in ...
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Discharge of static electricity

I watched this video about static electricity and I wanted to verify that I understand correctly. What we see in the picture is one lady touching with one hand this device that generates static ...
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1answer
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What is the difference between electric current and electric discharge?

We know that when we have 2 oppositely charged objects (As in static electricity for example), when one of these materials will come in touch with a neutral conductor, there will be a discharge - ...
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Conductors vs insulators with static electricity

I hope I can make this clear enough: I am trying to understand: what are the rules/constraints regarding to the materials that can produce static electricity? I'll start with what I know about ...
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1answer
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Is voltage a difference between two charged objects or two positions in a field?

I'm awfully confused about the concept of voltage. I know that it is "difference in electric potential between two points", and that voltage is always between 2 points. There is no ...
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Can a balloon and wool be seen as two terminals of a battery?

From what I understand, a battery produces potential difference across its two terminals. It does that by producing an accumulation of charges (positive charge in the positive terminal, negative in ...
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Is the concept of voltage poorly explained or is it just me?

Ok my cognitive barrier is this: All the videos I watched about "what is voltage" explains it pretty much this way: So there is an electric field which causes electrically charged objects ...
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Find 𝒗𝟏, 𝒗𝟐, and 𝒗𝟑 in the circuit in Fig. 3.14 using nodal analysis [closed]

Find ๐’—๐Ÿ, ๐’—๐Ÿ, and ๐’—๐Ÿ‘ in the circuit in Fig. 3.14 using nodal analysis
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How to generate electric current without a permanent magnet

The question is pretty simple: Can we build a device that coverts mechanical work in electric current1 without employing a permanent magnet and without access to any external source of current? The ...
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Is battery a capacitor that's being continuously charged?

Is it correct to say that a battery is like a capacitor which keeps being charged?
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If I touch the “+” side of a high voltage battery, will I get shocked?

Voltage is electrical potential difference between two points. When these two points are connected using a conducting material, current flows. So far so good? Let's think of a high voltage battery (I ...
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Can we say that space without electric field is of 0 potential?

Can we say that a given point in space, without any charges nearby, has no electric field, and thus the electric potential in this point is 0?
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Quick question regarding the meaning of Voltage of a Battery

Is the voltage of a battery simply the work necessary to move a unit charge from one extreme of the battery to the other? If this is the case, then when calculating the voltage of a battery the ...
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Meaning of Voltage in Ohm's Law

Ohm's Law states $$V=IR$$ where $V$ is te voltage, $I$ the current and $R$ the resistance. Since voltage is defined in terms of electric potential, and electric potential defined in terms of electric ...
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What is the connection between electric field and a battery?

Ok I'll start my question with laying some background: (Correct me if I'm getting things wrong - but don't be picky). Put electro-magnetism aside for this discussion - an electric field is some space ...
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Electricity basics

I've seen this video explaining Electrical Potential, and there's something I don't quite get. Ok so if I got this right - electric potential energy is the potential energy stored by a charge when ...
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Does having an electric potential difference necessarily mean having current?

I'm fairly newbie to these concepts, so please try to give a simply answer. Electric energy is often compared to gravitational energy. This analogy helps to understand the concept of voltage. With ...
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How does the speed of electricity become the same as the speed of light?

"The field due to the battery sets up a surface charge in the wire. The surface charge is negative near the negative pole of the battery, and positive near the positive terminal, and varies more ...
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What does an $x$ Watt bulb actually means?

Let's say I have a 11W bulb in my home, connected to a 220V power supply. What exactly does it mean that this bulb is 11W? As far as I know, the Wattage is determined by the formula $W = V * I$, so it ...
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What would an optimally designed (maximising the capacitance) capacitor look like? [closed]

I've just finished the chapter about capacitors on my textbook, and I have a question. So, there are problems in my textbook where the capacitance of different arrangements of charged surfaces is ...
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What does a battery produce? Is it Electric Potential Difference (EPD) or Electro Motive Force (EMF)?

I have read a lot of posts about Electro Motive Force, Electric Potential Difference and their differences, but I still confused. What I know is that EMF produces a EPD and keeps it constant, then ...
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What is the cause of triboelectric effect?

When a glass rod is rubbed with a silk cloth, glass rod loses electrons and silk cloth gains electrons. So, glass rod becomes positively charged and silk cloth becomes negatively charged. But why does ...
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1answer
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Why Electric field is same in a cross section of wire even if we change its thickness? [closed]

how does E remains same for the increased thickness. E is determined by field lines, if there is fixed number of field lines coming in then how it gets increased by increasing thickness of wire? To ...
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Electric shock?

If I spin a magnet really fast, and put my finger near it, i get no electric shock. However if i place a wire near that wire it will induce an emf across the wire, if i touch it, will i get a shock? ...
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What would be the electrical potential of a cable connecting two electronic devices on the magnetic poles of the earth?

The earth is a large magnet moving in the magnetic field of another large magnet the sun. can we have energy in this cable by electromagnetic induction? What would be the electrical potential of a ...
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Why voltage doesn't increase on adding two batteries with same potential across circuit? How Voltage is able to make a flow of current in a circuit? [closed]

Look at the image below. It shows that if two batteries with same potential on both terminals are added, charge on it must double and therefore giving double the $E$ (electric field) coming out of ...
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Why the displacement current is zero outside the capacitor?

Always when I study displacement Current it is zero outside the capacitor because the electric field is zero outside For example this photo Why this electric field on the surface s one is zero I ...
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How does grounding (burying a terminal underground) complete a circuit?

I am having some trouble with the concept of grounding the electric supply. The doubt is basically : if I hold a live wire standing on the ground, why do I get a shock?. Please don't say there exist a ...
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Heat dissipated by resistor formula question

The heat dissipated by a resistor is given by the formula $$ I^2 R $$ Any circuit portion has an equivalent resistance. Does that mean that the heat dissipated by any circuit portion, doesn't matter ...
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How does potential difference across resistor causes electrons to move through resistor?

I want just the answer for how a potential difference across resistor causes electrons in it to move? Also, How the speed of electricity becomes equal to C(almost) means the electrons at a very long ...
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1answer
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How is electric current possible if no electric field exists inside a conductor?

How is electric current possible if no electric field exists inside a conductor? Since no electric field exists inside a conductor. How is electric current possible as $$v_d=\frac{(eE)t}{2m},\;\;{E=0}...
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Tesla patented a device he believes gathered energy from light. (US 685,957 - Apparatus for the Utilization of Radiant Energy): [duplicate]

The invention is a sheet metal (top) place high above the ground. The sheet of metal is connected to a capacitor (the โŠ”โŠ“ shapes) connected to the Earth. (The other stuff on the right of the image is a ...
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What's the electric field inside a capacitor with AC current?

In DC-circuits the Electric field can be easily calculated under the conditions the field is homogeneous: $U = \int E \,\mathrm{ds} = E\,d$. Now I wonder what if you apply an alternating Voltage $U(t)...
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Can Atmospheric pressure be explained in terms of electrostatics?

I was wondering if the reason air pressure is so high in lower altitudes is due to the gases being more dense and therefore having a higher electrostatic potential,that's why air pressure at lower ...
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Electrical potential vs eletrical potential difference [duplicate]

I know this question was asked in some way or another, but my familiarity of concepts in electricity are very basic so I ask you to give an explanation using simple terms. I'm learning about Voltage, ...
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At what speed does a magnetic field form from the flow of current?

When an electrical current flows through a conductor and produces a magnetic field, does the magnetic field in the conductor form at the drift speed of the electrons in its structure or the velocity ...
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Does the static charge of an electrical circuit affect performance?

A positive static charge is the absence of electrons, and a negative charge a surplus of electrons. If an isolated electric circuit is subjected to a charge, does the performance change? Imagine a ...
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Simple trigonometric derivation in cathode ray tube

I want to calculate the distance from the origin where the electrons hit the screen: I've got: $$\begin{align} &s_1 = v\,t_1\\ \\ &s_2 = v\,t_2 \\ \\ &y_1 = \frac{1}{2}\,a_y\,t_1^2 = \...

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