Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

What is the internal resistance of a battery?

  1. Nov 15, 2006 #1
    Does a battery really have any internal resistance? If it has then what's the origin of the resistance.
    We know that the electrons flow from negative to positive terminal of a battery. Do the electrons just end up releasing energy(such as heat) at the terminal/ or combines with the atoms of the electrolytes available there/ or they move through the chemicals inside the battery between two opposite poles?
     
  2. jcsd
  3. Nov 15, 2006 #2

    Andrew Mason

    User Avatar
    Science Advisor
    Homework Helper

    The voltage across the terminals decreases with increased current flow. The battery itself will get hot as it delivers current. This means there is an internal resistance.

    By measuring voltage as a function of current, you can work out the resistance of the battery.[itex]R = (V_0 - V_I)/I[/itex] where V0 is the voltage with 0 current and VI is the terminal voltage when delivering current I to a load.

    AM
     
  4. Nov 16, 2006 #3
    Then it means that the battery itself is a load and electrons flow through it.
    Let's assume that, the battery used is a dry-cell battery. Now my question is:-
    Does this electron-flow contribute to the chemical change that occurs inside a dry-cell battery? I mean, whether some of the electrons are drawn from the flow and account for the chemical change inside the cell. Or whether electron flow and chemical change inside the battery are distinct event (which may effect each other, but are not same).
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?