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24 votes

How does a wireless charger work if there is no transfer of electrons?

The time-varying magnetic field created by the wireless charger induces an electromotive force in the wireless charging coil of the device. This electromotive force (after being rectified) drives ...
Vincent Thacker's user avatar
15 votes

How does a wireless charger work if there is no transfer of electrons?

Does the charged up battery have more electrons than the depleted one ? No. A charged battery has exactly the same amount of electrons as a depleted one. It is just that the electrons in the charged ...
gandalf61's user avatar
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13 votes

Why do charges exist in the first place?

I am going to assume that when you say "charges" you mean "electric charges" (there are some other types of charge in physics, but you probably haven't come across them). Why do ...
gandalf61's user avatar
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4 votes

Why do charges exist in the first place?

Aristotle said physics is the study of change and the main way that things change is through motion. Charges, via Noether's thm, are what is required for change to occur. For example, mass is the ...
Mozibur Ullah's user avatar
4 votes

Why does it not matter which way electrons flow in a circuit?

First, forget about electrons when analyzing electric current. While you may often model current flow in metals as electron flow, current is a more general concept. The electric currents in your brain ...
John Doty's user avatar
  • 21k
3 votes

How does a wireless charger work if there is no transfer of electrons?

You can think a wireless charger is similar to a power transformer where the primary coil is in the charger and the secondary is inside your device, including the necessary rectifier. Wireless ...
Ulrich Roos's user avatar
3 votes
Accepted

How could free electrons flow in a conductor? If electrons actually flow in a conductor, then won't the atoms of the conductor become unstable?

I wouldn’t call it unstable, but you are right in so far as, if you had a material with all charges bound in individually overall charge neutral atoms, that material would not be a conductor. For a ...
Zaph's user avatar
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3 votes
Accepted

Why does it not matter which way electrons flow in a circuit?

Electrons are already in the circuit before you close the switch, much like water is already in the pipe before you turn on the faucet. Electrons repel each other. Normally this is cancelled by the ...
mmesser314's user avatar
  • 38.7k
3 votes

Why do charges exist in the first place?

When an electron with a negative charge and its antiparticle, the positron, with a positive charge annihilate, one possible outcome is the production of two photons. This means that it is allowable, ...
Rich's user avatar
  • 829
2 votes

In magnetrons, is it the accelerating electrons or alternating fields within the anode that produce the microwaves?

A magnetron shoots a stream of electrons past a series of cavity resonators in a circle. A DC magnetic field bends the stream into a circle that passes by the resonator openings over and over again. ...
niels nielsen's user avatar
2 votes

Why does the energy (and thus frequency) of a photon entering glass stay constant if some is used up to accelerate electrons and slow down the light?

Your explanation of refraction is quite correct. The electric field of the light interacts with the electrons in the medium and we get an entangled system of light + electrons. This means the energy ...
John Rennie's user avatar
1 vote

Density of states - as a function of electron velocity

Consider electron gas moving in 1D ring with length $L$(in thermodynamic limit the boundary effects are not important), with periodic boundary condition, the single particle state can be written as: \...
Yakumo Ran's user avatar
1 vote
Accepted

Image of an electron

An "image" is formed from lots of light rays leaving the same object. For instance, when your eye forms an image of a symbol on your computer screen, like this symbol, $$ \sum $$ what's ...
rob's user avatar
  • 89.9k
1 vote

About lightning and lightning conductor

Of cause, if the lightning conductor does not work properly, lightning may set your house on fire or at least set the roof on fire ore damage it. But a well build lightning conductor should work to ...
trula's user avatar
  • 6,199
1 vote

Questions about batteries and circuits

does that mean that for every coulomb of electrons moving from the negative terminal to the positive terminal, they would lose 1.5eV of electrical potential energy? No, each individual electron ...
The Photon's user avatar
  • 27.6k
1 vote

Theoretical Electron Bunching paper, variable question

The phase $\varphi$ is just the phase of the oscillation in shown in figure 2 of the paper. There are lots of technical advantages to using the oscillating fields; in fact, that is much of what the ...
Buzz's user avatar
  • 16.1k

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