# Questions tagged [electric-current]

A measure of the rate at which electric charge is transported (especially through a circuit), it has units of charge/time.

1,730 questions
Filter by
Sorted by
Tagged with
2answers
3k views

### Why is it that potential difference decreases in thermistor when temperature of circuit is increased?

Why is it that potential difference decreases in thermistor when temperature of circuit is increased? From my understanding when temperature increases, there are more free electrons ($n$) so according ...
2answers
40 views

### What will happen if an ideal current source is connected to a isolated resistance?

I know that ideal current source is a theoretical thing. But when it comes to solve problems we have to consider these scenarios. Now suppose an ideal current source is connected with an isolated ...
1answer
59 views

### Classical Explanation for Electron-Ion collisions

Classically, electrons collide with other electrons and massive (by comparison), stationary positive ions as they conduct down a wire when an electric field is applied. Is there a good mechanism ...
2answers
37 views

### Current law explained

Kirchhoff's Current Law (KCL) is experimentally proven but what exactly happens?. I have made a model by taking the drude model and adding the interactions between the electrons and the reason why ...
1answer
37 views

### Electric current doubt

How to find out the direction in which the magnetic needle of a magnetic compass aligns itself when kept beside a current carrying conductor?
0answers
9 views

10answers
6k views

### Is every open circuit a capacitor?

I think that even open-ended wires can let AC current flow through them, just with a low capacitance. I also think an antenna could be a capacitor and open ended. Am I thinking correctly?
3answers
39 views

### Flow of charges inside a battery

I am having confusion about the flow of charges inside a battery which is connected to Circuit. Question is, do charges move from one end to another through the battery? If yes, how? Do they move ...
0answers
27 views

### Would the voltmeters give different readings in a circuit with induced current?

$\def\vE{{\vec{E}}}$ $\def\vD{{\vec{D}}}$ $\def\vB{{\vec{B}}}$ $\def\vJ{{\vec{J}}}$ $\def\vr{{\vec{r}}}$ $\def\vA{{\vec{A}}}$ $\def\vH{{\vec{H}}}$ $\def\ddt{\frac{d}{dt}}$ \$\def\rot{\operatorname{rot}}...
2answers
109 views

### How does back emf occur if a system can’t do work on itself? [closed]

If a coil is connected to a battery and the current starts up, the electrons have to be moving at a certain speed through the wire and therefore have a certain kinetic energy. But if they are moving ...
2answers
48 views

### Is there Electric Flux through a closed loop around a current wire?

In one of his lectures, Professor Walter Lewin is ammending Ampère's Law to include displacement current (i.e. It not only depends on the current that penetrates the loop, but also on the changing ...
0answers
35 views

### Why is current-density a vector? [duplicate]

I was told that current has a direction but does not follow vector-laws, so it is a scalar quantity. That's okay. I thought it through Kirchoff's junction law: assume two currents joining at 90 deg, ...
2answers
39 views

### Empty and fresh battery in series

If you have 2 (e.g. 1.5V) batteries in series and one is dead/empty, what is the reason why a device is not working? Lack of voltage (1.5 + 0 is simply not enough for the device to operate)? From my ...
0answers
27 views

### Why do we change signs arbitrarily while calculating RC circuits formulas?

When I have to calculate the formulas regarding RC circuits, for example the process of charging a capacitor, there is a discrepancy between my calculations and those of all the books I can find. Let'...
0answers
31 views

### How does current flow between two adjacent corners of a thin plate when voltage is applied?

If it was an infinite plate then current would have radial symmetry both at A and B. This is a finite plate I'm vehemently against the idea of current having radial symmetry because that will lead ...
1answer
5k views

### Why does electrical current start to flow?

What happens microscopically when an electrical current starts to flow? I'd like to understand microscopically what happens in detail when electrons start moving (quasi-classically). Electrons can ...
3answers
74 views

### Why is the current same after and before passing through a resistor? [closed]

•Why is the current same after and before passing through the resistor ? •Why is a voltage drop across the resistor ? Explanation in terms of electron flow and electric field will be really helpful. ...
2answers
429 views

### When the voltage is increased does the speed of electrons increase or does the electron density increase?

I am just a high school student trying to self study, please excuse me if this question sounds silly to you. I know that current is a product of the speed of electrons and the electron density.When ...
2answers
53 views

### Potential drop in slide wire (Potentiometer Experiment)

While doing the potentiometer experiment I was taught that the galvanometer will show opposite deflection on opposite ends of the slide wire. My questions are as follows: Why does this happen? In ...
3answers
60 views

### What actually current is? [closed]

Somebody help me visualizing current. What is it actually? Not just with mathematical relations but with something that we can visualize too.