Are you asking how a battery works?engineeringstudnt said:
no i know how battery's works :) . Terminals create potential difference so that charge flows on wire. my question is: point A and point B has same amount of electrons in time=t let's say(because the current is same).But why there is a potential difference in theese points :)PeroK said:
I thought that was because of the battery! Take the battery away and you have a neutral wire.engineeringstudnt said:
lets say we stopped to time for a while. in point A we should saw x electrons and point B we again saw x electrons(because the current are same I=Q/T) . x-x=0 but there should be a potentail difference right ? that is point what i don't understandPeroK said:
The battery creates an electric field, which produces the current.engineeringstudnt said:
The voltage across the resistor isn't related to the relative amounts of charge passing through either terminal of the resistor (which, as you note, are the same), but rather the relative potential energies (per unit charge) of the charges at either terminal of the resistor.engineeringstudnt said:
thanks for you answer but honestly i still didnt quite get it i guess i should read more :)ergospherical said:
Did you know that Werner Heisenberg nearly failed his PhD examination because he didn't know how a battery works?engineeringstudnt said:
engineeringstudnt said:
In an Ohmic material of length ##d## and resistance ##R##, there is an electric field given by ##E = IR/d## (this comes from a more fundamental relationship ##j = \sigma E##). As the charges flow through the resistor, the electric field does an amount ##Ed = IR## of work on them. Equivalently, it can be said that the electric potential energy (per unit charge) of the charges decreases by ##IR##. This energy is ultimately transferred to the ions in the metal, becoming heat.engineeringstudnt said:
Think of a river flowing downhill. Look at a higher point and at a lower point on the river. There is the same amount of water flowing at both points, but the water has a higher potential energy at the higher point than at the lower point. The amount of water flowing is analogous to the current, and the height of the water is analogous to the voltage.engineeringstudnt said:
thanks for the analogy that's actually really helped.but one question if electrons loses of some of their energy when they passed the resistance don't they lose their speed too ? so if its the case current shouldn't be same at the point A and B but they are :d.?phyzguy said:
They lose potential energy when the electric field does work on them, but it's assumed that their drift velocity (and therefore also their averaged kinetic energy) is constant. You can imagine that the "excess" kinetic energy gained due to work done by the electric field is immediately transferred away to the ions in the material.engineeringstudnt said:
i really appreciate that thank you very much i get it now :)ergospherical said:
So just to follow up to clear up your notation going forward...engineeringstudnt said:
Just to be sure, if you are not solid on what "drift velocity" is you should look it up.engineeringstudnt said:
Ohm's law is a fundamental principle in physics that describes the relationship between voltage, current, and resistance in an electrical circuit. It states that the current through a conductor is directly proportional to the voltage applied, and inversely proportional to the resistance of the conductor.
Ohm's law is used in a variety of practical applications, such as designing and analyzing electrical circuits, calculating the power consumption of electronic devices, and troubleshooting electrical problems. It is also used in fields like electrical engineering, telecommunications, and electronics.
Voltage is measured in volts (V), current is measured in amperes (A), and resistance is measured in ohms (Ω). These units are named after the scientists who contributed to the development of Ohm's law: Georg Ohm, André-Marie Ampère, and Georg Ohm.
Ohm's law is applicable to most types of circuits, including direct current (DC) circuits, alternating current (AC) circuits, and even complex circuits with multiple components. However, it may not be accurate for circuits with non-linear components like diodes and transistors.
In a series circuit, the components are connected in a single path, so the current remains the same throughout and the voltage is divided among the components. In a parallel circuit, the components are connected in multiple paths, so the voltage remains the same across each component and the current is divided among them. Ohm's law can be used to calculate the total resistance in a series circuit and the equivalent resistance in a parallel circuit.