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

learn more… | top users | synonyms

-3
votes
0answers
42 views

Which electrons in copper are involved in electric current flow?

That the bounded to the nucleus inner electrons are not involved seems clear to me. But how much of the electrons from the outer shells are involved? The last two shells are 3d10 and 4p1 (for nickel ...
2
votes
1answer
471 views

Wave superposition, is my textbook wrong?

Here's the question: Two coherent electromagnetic waves are incident simultaneously at some point in space. The intensity of each independent wave is $I_0$. What is the intensity of the superposition ...
0
votes
0answers
7 views

Why the Amount of electric field generate from any small surface of a body is equal to the electric field generated from remaining surface left out?

Recently I just read one property of electrostatics which states that: The amount of electric field generate from any small surface is equal to the electric field generate from remaining surface ...
0
votes
2answers
37 views

Does resistance have to be constant for Ohm's Law to be obeyed?

I have looked all over the internet to try and find an answer to this question and frustratingly different people seem to have completely different opinions. What I find hard to understand is why ...
2
votes
3answers
70 views

Electric field or static electric field around a plugged-in lamp cord (when lamp is not turned on)?

When an electrical cord from, say, a lamp, is plugged into an AC wall socket, I'm aware that an electric field forms around the entire length of the cord and even before the lamp switch is flipped on. ...
1
vote
0answers
26 views

Is there an electric field in the direction of a uniform current?

In an infinite plane where uniform current is passing through,is there any electric field? Because i know that charge produces an electric field but in a uniform current and because it is an infinite ...
-3
votes
0answers
23 views

AS Level Electricity Question - Cube of Resistors [on hold]

Twelve equal resistors are connected to make the edges of a cube. Thus each resistor is connected to two others at each end. A power supply giving $6.0\mathrm A$ is connected between two diagonally ...
1
vote
1answer
44 views

What is the amount of charge density in a metal wire for the electron's which are involved in current flow?

According to the question Why is charge = nALe n is the charge density (number of electrons per unit volume). Which of the electrons in a metal wire are involved in current flow? Only the unbounded to ...
0
votes
1answer
29 views

Do electrons lose energy between the battery anode and cathode?

In a battery circuit, does an electron leaving the anode carry more energy with it than an electron returning, from having been through a machine, to the cathode? If not, how does the battery deliver ...
0
votes
1answer
26 views

Electrical conductivity of metals on heating

What effect does heating have on metals (to be specific, on the electrical conductivity) ? And why does it have that effect?
1
vote
1answer
32 views
+50

What really happen with resonance inductive coupling

I can't figure out the picture of resonance inductive coupling I can image how magnetic inductive coupling works, It scatter magnetic around one coil and if second coil being near it then induce ...
3
votes
1answer
43 views

Why do I see different color sparks from the 2 pins when I plug an appliance in a socket?

I plugged in the charger of my laptop into a socket, which I have done a lot of times but this time, I noticed a strange thing. When the contact was made between the pins of charger and the socket, ...
1
vote
1answer
24 views

Why doesn't the electric potential constantly decrease in a circuit as the current moves from the positive to the negative terminal?

Why doesn't the electric potential constantly decrease in a circuit as the current moves from the positive to the negative terminal? Details and Assumptions: 1. The wires show no resistance.
3
votes
4answers
124 views

Can electricity flow through vacuum?

People say yes, and give a wonderful example of vacuum tubes, CRTs. But can we really say that vacuum (..as in space) is a good conductor of electricity in a very basic sense?
1
vote
1answer
35 views

At what distance is lightning dangerous for someone lying down?

My 8 yo child told me that they learned at school that they should lay down flat on the ground in case of lightning. I told him that the more correct position is crouching down with feet together, but ...
0
votes
0answers
16 views

How many kind of effect which generate electricity [closed]

I know there are Piezo/Pyro/Thermo/Chemo/Photoelectric I want to get a complete list of all these effects include in theory Where can I find this information?
0
votes
0answers
19 views

What is the theoretical reasoning behind calculating emfs in series or parallel?

First off, I did some research on my own but the answers weren't satisfactory. The analogy of the water pump makes zero sense as I see no way how "Potential" is even comparable with "Dynamic ...
1
vote
1answer
38 views

Why do nuclear bomb explosions create an array of visible electric discharges in the form of lightening in the upper atmosphere?

I've seen videos on the internet, showing nuclear bomb test explosions, and there appears to be a large amount of visible lightening discharging numerous times over the development of the mushroom ...
0
votes
1answer
49 views

How do the electrons know the route?

I've learnt in classroom that the requirements for electrical current to flow in a circuit are as follows: there must be a closed conducting path between negative and positive terminals there must ...
1
vote
1answer
16 views

When I put 2 electrodes into a electrical conductive solution, does the volume of the solution around the electrodes have biological effect?

Media these days give me a common sense that it is able to hurt someone if they step on a wet floor with a electric cord dipped in, several movies have this scene.However, I wonder if I set up an ...
0
votes
0answers
17 views

Is the induced EMF dependent on the conventional or actual flow of electrons?

I have been studying Faraday's Law and Lenz's Law and the flow of current to oppose change in flux linkage. My question is whether the actual flow of electrons to the top of a material makes the EMF ...
0
votes
2answers
34 views

How does electric energy flow in a circuit? [duplicate]

I have read that the electric energy flows from the battery into the circuit through electric field created outside the wires into the light bulb (or any other resistor). I have also read that the ...
-1
votes
0answers
19 views

Resolution to a hotly debated question: Which is more dangerous to humans, amps or volts? [duplicate]

Many times I have heard many a self-reputed wise internet sage quote, " 'Tis the amps that kill.' I really don't think so, at least, I don't think that applies all the time. Shouldn't volts be just ...
2
votes
2answers
47 views

What is the voltage of an average carpet static shock? Can you make it lethal?

I think I heard somewhere that it was in the thousands of volts, but it had extremely, extremely low amps. Could you somehow transform the current to make it larger or something? Or does the equation ...
0
votes
2answers
35 views

How does my car's remote keep running?

Two years ago, I got a new car. It comes with a wireless remote that provides keyless ignition and can unlock and lock doors at the press of a button. Just recently, I read somewhere (unfortunately ...
-1
votes
1answer
15 views

Electrostatic, electromagnetic, electric, field, force, e.m.f, p.d [closed]

Can someone explain the difference between electrostatic force, electromagnetic force, electrostatic field, electric field, magnetic field, electromagnetic field, electromotive force, potential ...
0
votes
1answer
38 views

The influence of electric potential of a planet to a spaceship

How does the electric potential of a planet influence a spaceship? If a distant planet is at very high potential compared to Earth. A spaceship is sent from Earth to land on the planet. Is the mission ...
0
votes
0answers
28 views

AC is more dangerous or DC? [duplicate]

If, though not possible DC also works on specified frequency or follows sine wave form then which one would be more dangerous AC or DC?
1
vote
0answers
26 views

How do I show $e_r$ and its first- and second time derivative?

What does a charge q moving in a circular orbit with a constant velocity (a "rotating charge") and a stationary observer that measures the E field look like? And how do I show $e_r$ and its first- and ...
0
votes
1answer
50 views

Why isn't the magnitude of the electric field in a circuit zero?

I've been re-reading my knowledge of circuits and how current flows as well as the surface charge distributions in the steady state, since it's been quite some time and we've just started studying ...
0
votes
1answer
37 views

What does an increased time constant of a capacitor do?

If a capacitor is being charged to any voltage, what effect would increasing the time constant have on it and if a graph of Charge Q/Time T was plotted to give a positive decreasing gradient, how ...
1
vote
1answer
24 views

Is battery the supplier of charge in an electric circuit?

In a simple electric circuit consisting of wires, battery and a bulb... Are the charges which flow in the circuit provided by the battery or are they coming from somewhere else?
0
votes
0answers
43 views

Question about DC & AC Generators

Main question: moving a alternating magnetic field past a coil can create AC, if the same pole is moved past repeatedly does this still generate the same amount as the AC version would? or is the ...
0
votes
3answers
49 views

How much work do I need to convert 300ml of water from 25°C to 3°C? [closed]

A question on how to apply thermodynamics principles to figure out how much work is needed to hold 300ml water in room temperature at 3°C. So far I have: 1Cal for each degree per g of water. We have ...
0
votes
0answers
36 views

Since when do humans know about electric charge? [migrated]

We know that the electron was discovered in 1897 by J.J. Thomson. So was the knowledge about charge, current, electricity and all those terms related to it which we study today discovered after it, or ...
0
votes
1answer
19 views

Why the electrons flow from higher potential to lower potential?

We know that every thing moves from a higher potential to lower potential. In fact we also studied in our textbooks that a charge travels from higher potential ie. Positive side to lower potential ie. ...
0
votes
1answer
20 views

How can we know that a particular charge is positive or negative?

Suppose I am provided with a positive is charged....and someone tells me to find which type of charge is present in it? Then how can we detect that the body is positively or negatively charged? Is ...
1
vote
1answer
31 views

Is electric current a scalar quantity?

According to the definition of a Scalar quantity that i have read in class 9 is that ''those quantities which has only magnitude but no direction is known as a scalar quantity''.....But in class 10 i ...
1
vote
2answers
55 views

Energy conversion (conceptual) question

Suppose I have a electronic car. It runs by electrical energy. So when wheels rotate, mechanical energy is produced. Then why can't we convert it back to electric energy and produce somewhat unlimited ...
0
votes
2answers
38 views

Why doesn't current induced by changes in flux affect the flux, while current induced by a battery does?

Faraday's law states $V=-\frac{\mathrm{d}F}{\mathrm{d}t}$, where $F$ is flux. Since $V=IR$ for passive circuits, $I = V/R = -\frac{1}{R}\frac{\mathrm{d}F}{\mathrm{d}t}.$ But by the Biot-Savart law, ...
0
votes
0answers
15 views

How does the phase of an alternating current change when flowing through a multi-layered material?

I have questions regarding the properties of the alternating electrical current in the following imaginary experiment: There is an AC (sinusoidal wave with frequency $f = 5\ \mathrm{Hz}$). I would ...
1
vote
2answers
56 views

How to calculate temperature of an incandescent bulb filament?

Suppose we have a light bulb, for which we know its power rating, like voltage of $12\mathrm V$, and power consumption of $10\mathrm W$. We also know it's a halogen bulb with a tungsten filament ...
1
vote
0answers
10 views

Wave velocity (R)LC circuits.

I'm attempting to simulate some fluid like mechanics using circuits. Specifically wave propagation. I am attempting to measure the wave propagation velocity using an oscilloscope on the circuit below, ...
0
votes
0answers
39 views

Does earth conduct electricity?

if we connected a voltage source with its two terminals in the earth does it conduct electricity ? and why they use something like " ground or earth " in safety to let the residual charges go to the ...
4
votes
0answers
19 views

How can the effects of temperature be accounted for in-situ electrical resistance corrosion monitoring?

In reading the Berkeley Lab's article Rust Never Sleeps, where research is underway investigating the use of iron oxide rust as a photovoltaic, they state: Rust – iron oxide – is a poor conductor ...
0
votes
1answer
35 views

How to find the distribution of charge on two spheres connected by a conducting wire?

A solid metal sphere of radius $R$ has charge $+2Q$. A hollow spherical shell of radius $3R$, concentric with the first sphere, has net charge $-Q$. What would be the final distribution of the charge ...
0
votes
0answers
24 views

Does lightning have a thickness?

We have calculated (probably measured) the speed, temperature and voltage of lightning so does lightning have a thickness? Note: When a lightning occur it heats up the air rapidly causing the air to ...
0
votes
0answers
23 views

What does this mean: “Quantity of charge in one equivalent ”

I had the following question on my test today: "What quantity of electric charge is in one equivalent of electrical energy" At least it was roughly phrased like this. Even on the test the question ...
0
votes
0answers
14 views

If we study an electric wire under Scanning Electron Microscope (SEM), what will be the effect of the current on the microstructure or image?

If we study an electric wire under SEM, what will be the effect of the current on the microstructure or on the image obtained from SEM? I will elaborate it a bit more: if we change the current in ...
0
votes
2answers
66 views

Can a laser work forever if constant electricity is provided?

Can a laser work forever if constant electricity is provided? If we take a laser and provide it with constant electricity will the reactions in the semiconductor generate photons forever?