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

Homework Help: Concept of Battery

  1. Mar 17, 2008 #1
    Could someone explain the concept of a battery
    I've looked it up in my text book and wikipedia, but it doesn't really help

    Here is what I think I understand
    1. Charges (electrons) are made in the cell by chemical reactions
    2. They complete the circuit by leaving one of the terminals and returning to the other.

    So my questions are
    1. Which terminal are the charges made at and which terminal do they leave to go through the circuit?
    2. After completing the circuit, how do the charges move from one terminal of the battery to the other?
    3. How is potential difference involved in this?
  2. jcsd
  3. Mar 18, 2008 #2
    Instead of battery, search Wikipedia for 'electrochemical cell'. A battery is made up of a bunch of electrochemical cells bundled together.
  4. Apr 4, 2008 #3
    i wn to know about Ah in battery..what is the current produce in 12 V dc at 7 Ah that have been rate 10 hours?
  5. Apr 4, 2008 #4
    The external electric field of a battery is similar to a dipole. Since a potential difference is created by the battery, the electrons aim for the higher electric potential (or lower potential energy state), and their route would be through the circuitry. Once they reach the battery terminal, they do go through the battery...so its sort of as though the charges run through the circuit while losing energy and reload as the pass through the battery (I'm not sure on how the charges move through the battery). Electric field is propogated by a battery and once the charges start moving in the circuit, you can look at it as an electric field running along the wires/circuitry. Charges do not move fast across a circuit (they actually move at a slow average speed) and the battery does not provide for the charges, it provides for the necessary voltage, which for batteries is called emf; the charges are available at all points in the circuit and the battery provides an electric field that moves the charges (electric fields are able to travel at the speed of light)...so when a circuit is closed by a switch, the reason why the device works seemingly instantly is because the electric field is able to propogate at high speeds and charges at considerably all parts of the circuit start moving almost simultaneously.
    Last edited: Apr 4, 2008
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook