# Tagged Questions

3answers
49 views

### Does an electron move in a conductor?

The definition of current is flow of electric charge. But recently I have heard that the electrons cannot move, that they just transmit energy to the other electrons and so on.
3answers
59 views

### The measurement of electricity

I'm a student trying to understand electricity. As I learned from school, electricity is the flow of electrons, but I'm confused about the measurement of electricity. As I learned, voltage is the ...
3answers
61 views

### What really is resistance? How does it generate heat?

OK I know that R= V/I. I also know that R = ρl / A But what I want to know is that what really causes resistance? Is resistance equivalent to force? or is it just a constant? Also, what causes ...
2answers
81 views

### Can we pass electricity through air?

Electricity: I was wondering, whether we can pass electricity through air over a distance of 100 meters or so as electricity means the flow of electrons and we have seen the discharge or movement of ...
0answers
30 views

### Numeric value of the electrons drift velocity in superconductors

Somebody knows the numeric value of electrons drift velocity in superconductors? How this value depends from the used superconductor material? What's about the current? Since the electrical resistance ...
0answers
15 views

### Origin of Overpotential in Electrochemical Cell

I'm well aware of the significance of overpotential and how it is defined to be the difference between the thermodynamically determined equilibrium potential and the experimental potential required to ...
3answers
114 views

### How do substances with like charges repel each other?

I have read in a number of places how substances with opposite charges attract each other: The excess electrons in the one substance repels the electrons in the other substance so that they move away ...
2answers
87 views

### Why can't an excess of electrons or holes by themselves cause current flow?

I am a beginner in electrical engineering. Often times (most cases actually), the underlying physics aren't really explained to us and we are just left to assume that it works "because it works." This ...
3answers
141 views

### How “earthing” electricity work?

I made a simple bulb-battery circuit and then I cut one of the wires and attached both ends to cemented floor, the bulb didn't glow, this means cemented floor is a ...
1answer
38 views

### Can electrons coincidentally flow along a circuit to cause current?

My understanding of circuits which are not supplied an e.m.f. is that the electrons randomly just flow about in random directions, and since there's so many of them, probability dictates that any ...
1answer
89 views

### The probability of electron-hole pair recombination as a function of physical proximity

When we shine line of an appropriate wavelength at a metal, e.g. gold, such that there is sufficient energy to promote an electron from the valence band to the conduction band, we'll generate with ...
0answers
48 views

### Drift velocity of electrons in a superconducting loop

Do electrons travel at the Fermi velocity in a superconducting loop? For metals the Fermi velocity seems to be around $10^6$ m/s. So would electrons (in a Cooper pair) travel around the loop at this ...
1answer
77 views

### Question on static electricity & electron transfer

Static electricity is caused by the transfer of electrons between substances right? For example, take a balloon and your hair. Both are stable and electrically neutral. So why would electrons jump ...
3answers
200 views

### How does electricity flow?

The terminals of the batteries set up an electric field in the wire. Surface charges build up to ensure the field is perpendicular to the wire. This allows the electrons to move through the wire. But ...
1answer
285 views

### Batteries and voltage?

The voltage of a battery gives you the difference in potential energy 1C of charge would have at the positive terminal vs the negative terminal. If I connect a wire to both terminals, the battery ...
0answers
49 views

### Why are free electrons always moving?

Electrons move when a field acts on them. If the electrons move towards the field, they cancel out the field when enough electrons build up. Shouldn't the free electrons stop moving eventually and ...
1answer
121 views

### The workings of the Hall effect?

I want to ask about the workings of the Hall effect. Why do the electrons come to rest on the edge of the wire? The magnetic field pushes them up, and the electric field pushes them forward. Shouldn't ...
1answer
122 views

### In a positively biased PN junction, where do the injection carriers come from?

I am not quite understand i-v character of PN-junction diode. Here is the model in textbook. The PN junction diode can be divided into three regions. They are One depletion region near the PN ...
3answers
247 views

### Why don't we use beta radiation for making electricity?

Why don't we use beta radiation to make our electricity? Since it is an electron being released/made, it would make sense to try and capture it. But, we obviously don't so. What am I missing in my ...
1answer
120 views

### How does current work

In all diagrams i have ever seen of circuits it's implied that electrons travel through load/bulb and bulb makes light/heat. Now there is a problem here...because of this implied logic i assumed more ...
3answers
207 views

### Why does Joule heating not occur when no current flows through a conductor?

Joule heating happens every time when the conduction electrons transfer kinetic energy to the conductor's atoms through collisions, causing these conductor's atoms to increase their kinetic and ...
2answers
1k views

### Path of least resistance vs. short circuit

Some sources on the web claim that "electricity follows the path of least resistance" is not true, e.g. this physics SE question. However, in every explanation of "short circuits", the author says ...
2answers
287 views

### Why does a cathode have to be heated to emit electrons?

Considering that electrons are highly mobile inside of a metal, why do they have such a tough time getting out at the edge of it and continuing their trip ballistically?
2answers
7k views

### Definition of electric charge and proper explanation

Is there a definition of electric charge and proper explanation of it? It is said "Electric charge is the physical property of matter that causes it to experience a force when close to other ...
1answer
269 views

### Joule heating due to the (slow) electron drift velocity?

I understand the concept of why the signal speed is higher than the electron drift velocity, but I can't understand the concept of joule heating. If electrons move slow then how do they produce a lot ...
1answer
2k views

### How electrons act under rotating magnetic field?

I study Power Engineering in University. Today I asked my lecturer to explain me exactly how atom's electrons act under spinning rotor's magnetic field, that generated dynamic electricity. But he even ...
0answers
45 views

### pressure required for displacing a single electron off a crystal

I need to know this for my project- "power generation using the pressure applied on a keypad of a mobile electronic device". How much pressure does it take to displace a single electron off its ...
1answer
55 views

### Microscopic fields inside a conductor

In a neutral conductor if we assume electrons as point charges, the electric field in the space between them cannot be identically zero. This microscopic field may be very weak. What if we were very ...
3answers
3k views

### Where do electrons in electricity come from?

Where do the electrons come from when an electric generator is making electricity? Is from the air? Would a generator work in a vacuum? Electrons have mass so where would they be pulled from if ...
2answers
1k views

### How exactly does static discharge work?

Assume I have built up a pretty high charge by rubbing the floor or something. I want to understand these situations: I almost always get shocked when I touch a metal doorknob with my bare hand. I ...
3answers
5k views

### is it possible to flow current in open circuit?

First , i don't know much about chemistry and physics. I'm just a graphic designer but i have this question in my mind. I'm sorry if this question is too basic and use 'generic' language. As i know ...
2answers
139 views

### A problem concerning the force between currents or moving electrons

Concerning two identical wires carrying the same current (same direction, speed and magnitude), they will be attracted because of the Ampere force. But when I was in the frame moving with the same ...
1answer
425 views

### Excess charge on an insulator and conductor

So I was recently wondering what happens to the excess charge when it is placed on an insulator or conductor e.g. rubbing two objects together. I know in the conductor the electrons are free to move ...
1answer
573 views

### Relativistic drift velocity of electrons in a superconductor?

Is there a formula for the effective speed of electron currents inside superconductors? The formula for normal conductors is: $$V = \frac{I}{nAq}$$ I wonder if there are any changes to this ...
3answers
364 views

### Can I get anions by touching the negative electrode of a battery? [closed]

It is said that anions are good for health. Instead of using an anion generator, can I get anions by touching the negative electrode of a battery?
1answer
2k views

### How to know what materials are good conductors of electricity?

I'm not asking a question like "Is the wood conductive?". No. I'm asking what properties do they have to have to be good conductors. Theoretically I mean. Thanks.
1answer
864 views

### Definition of Free Electrons and Mobile Charges?

Could someone please give me a good definition of the following electric terms? Despite what searching I have done, I have not come across a definition that I have found clear for me to understand: ...
3answers
456 views

### Current in a simple circuit

I was going over my notes for an introductory course to electricity and magnetism and was intrigued by something I don't have an answer to. I remember my professor mentioning, to the best I can ...
7answers
9k views

### Why is the charge naming convention wrong?

I recently came to know about the Conventional Current vs. Electron Flow issue. Doing some search I found that the reason for this is that Benjamin Franklin made a mistake when naming positive and ...
4answers
2k views

### How do electrons “know” to share their voltage between two resistors?

My physics teacher explained the difference between voltage and current using sandwiches. Each person gets a bag full of sandwiches when they pass through the battery. Current = the number of people ...
11answers
6k views

### Does 'electricity' have mass? Is 'electricity' tangible?

Background: I'm in a legal academic discussion about the status of electronic 'goods' and whether they qualify as 'goods' in the same way a chair and a pen do. In this context (and specifically at the ...
6answers
1k views

### Is electricity instantaneous?

My question is basically what exactly is electricity? I've simply been told before that it's a flow of electrons, but this seems too basic and doesn't show that electricity is instant. What I mean is ...