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 power to a machine to function by simply transferring electrons from anode to cathode via a circuit?
[Physics] Do electrons lose energy between the battery anode and cathode
electricity
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Electric current is the rate of flow of electric charges across any cross-sectional area of a conductor. The direction of electric current is taken as the direction of flow of positive ions or opposite to the direction of flow of free electrons. Your assumption is not necessary here... Electrons always flow from negative terminal to positive terminal.
$$i=\frac{dq}{dt}$$
When current flows through an electrolytic solution or during the process of electrolysis, The plate towards which positive ions (cations) flow is called the cathode and the plate towards which negative ions (anions) flow is called the anode.
Wikipedia says clearly,
In an electrochemical cell, The electrode at which electrons leave the cell and oxidation occurs is called anode and the electrode at which electrons enter the cell and reduction occurs is called cathode. Each electrode may become either the anode or the cathode depending on the direction of current through the cell. A bipolar electrode is an electrode that functions as the anode of one cell and the cathode of another cell.
So, the convention is totally based on our definition of the direction of current flow that it always flows opposite to the direction of electrons (i.e) electrons can be called as cations or anions depending on the usage. And based on this, we dump our thought that cathode should always be negative, etc...
When the electron strikes the anode there are many ways it can dissipate it's 24eV worth of energy. It could eject an electron from some atom in the anode, and that excited atom could emit a photon as it recombines with an electron, however it is vastly more likely that the energy will end up as lattice vibration i.e. heat. The amount of radiation emitted from the anode is very small, but it does happen and is used as the basis of soft x-ray emission spectroscopy.
In any case 24eV would be an exceedingly soft X-ray, if it could be called an X-ray at all. At that energy any radiation would be rapidly absorbed by pretty much everything including the glass of your valve.
Re your second question, in the absence of the anode the photoemission would charge the cathode and increase the work function. So you'd get some photemission as first, but it would stop after a while. With the anode I guess the electrons would indeed arrive with more than 24ev energy.
Best Answer
Electric current is not a flow of energy; it's a flow of charge. Charge and energy are two very different things.
An electric current is a flowing motion of charged particles, and the
*particles do not carry energy*along with them as they move. A current is defined as a flow of charge by I=Q/T; amperes are coulombs of charge flowing per unit time. The term "Electric Current" means the same thing as "charge flow." Electric current is a very slow flow of charges, while energy flows fast. Also, during AC alternating current the charges move slightly back and forth while the energy moves rapidly forward.Electric energy is quite different than charge. The energy traveling across an electric current is made up of waves in electromagnetic fields and it moves VERY rapidly. Electric energy moves at a completely different speed than electric current, and obviously they are two different things flowing in wires at the same time. Unless we realize that two different things are flowing, we won't understand how circuits work. Indeed, if we believe in a single flowing "electricity," we will have little grasp of basic electrical science.
In an electric circuit, the path of the electric charges is circular, while the path of the energy is not. A battery can send electric energy to a light bulb, and the bulb changes electrical energy into light. The energy does not flow back to the battery again. At the same time, the electric current is different; it is a very slow circular flow, and the electric charges flow through the light bulb filament and all of them flow back out again. They return to the battery.
Electric energy can even flow in a direction opposite to that of the electric current. In a single wire, electric energy can move continuously forward while the direction of the electric current is slowly backwards. In AC circuits the energy flows continuously forward while the charges are alternating back and forth at high frequency. The charges wiggle, while the energy flows forward; electric current is not energy flow.
for more information visit this website
http://amasci.com/miscon/eleca.html#current
William J. Beaty Electricity Misconceptions