Basic power and energy question

[Abhishek_Anand]

Let's say we have a source of electrical energy, in form of a battery or some other source. We then connect a load to it. The source creates a potential difference across the load and drives a certain amount of current through it. The amount of current depends on the load. We know that, current is just a flow of electrons and the electrons leave the source at one end and then enter back into the source at the other end. Now, what is it that delivers power to the load. I want to know how the transfer of power or energy is taking place here. What do electrons loose in this process and how does the source fill the electrons with the capacity to do it. If the current leaving the source and the current entering the source are equal what is lost there?

 

[Usama Siddiqui]

The actual dissipated energy is what gets wasted in form of heat,suppose if its a resistor its v^2/R ,the actual power supplied = to the power dissipated,it means that the source continuously provides the power untill this equation is stable,if the power dissipation is more then the source (thats what happens when there continuous supply of constant current) then the battery gets drained. theres no hard and fast rule that the current entering is equal to the one leaving its just a convention.

 

[WimRFP]

The current is the same (as mentioned), but you need to exert a force on the electrons to keep the electrons going. See it as pushing water through a narrow pipe, you need a pressure difference the keep the water flowing. The electrons lose speed due to collisions. The collisions generate heat.

Force on electrons is exerted via the E field (F = q*E), q = charge of electron, E = electric field in V/m, F is force in N.

V = E*s V is voltage in V, s = distance, in a uniform field, you can also say E = V/s, s is distance.

The Volt (unit of voltage) is defined based on energy. Imagine you have a certain electric field and you would move 1 Coulomb of charge (Q). If you need 1J to move this 1 Coulomb charge From A to B. The voltage between B and A is 1V so V = En/Q (V = voltage, En = energy, Q is charge).

Because of voltage is directly related to energy: En = V*Q is valid Differentiating Q gives electrical current I (I = dQ/dt). Differentiating Energy gives power (P in Watt), hence:

P = U*I.

 

[Abhishek_Anand]

As far as I get this, the source creates a potential difference in the path so that electrons can flow, just a water flows from a height to the ground. And, the electrons have potential energy in them, which they loose when they come across a load, of any kind.
Am I right? Does this explanation need any correction??