Question

Very detailed explanation on how a battery operates. The theory in the internal resistance of batteries, how charge is created, EMF, Electrochemical reaction in batteries, etc.

Answer 1

Components of a Battery - Two terminals and an electrolyte medium. Terminals are made of different metal and the electrolyte, which separates these two terminals is usually chemical medium that allows the flow of electrical charge between the terminals.

Working - The chemical on the anode releases electrons to the negative terminal and ions in the electrolyte through what’s called an oxidation reaction. At the positive terminal, the cathode accepts electrons, completing the circuit for the flow of electrons converting stored chemical energy into useful electrical energy. This electrical energy is then used to operate lights etc.

If we talk about internal resistance of batteries, almost all the real batteries have internal resistance. A source with pure voltage is usually called as an EMF. Therefore, if we want to represent a battery then we can do so by putting an emf in series with a small resistance which indicates the internal resistance of the battery.

Therefore, voltage of battery is written as

V = E - Ir

where E is emf and r is internal resistance.