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Batteries and Charges

  1. Apr 6, 2008 #1
    Inside the battery (we stress INSIDE the battery) in a closed circuit (consider the battery attached to a lightbulb with the light bulb glowing), the battery

    (a) creates positive charge.
    (b) pumps positive charge from its positive terminal to its negative terminal.
    (c) creates negative charge.
    (d) pumps positive charge from its negative terminal to its positive terminal.

    I think that batteries pump current (positive charge) from the positive terminal to the negative terminal, because if batteries work due to an electric field, then the positive current would have to move toward the negative terminal. So based on this I think the answer is B. But batteries produce electrostatic potential energy so doesn't that mean it would create positive charge (A) as well?

    So I guess I would go with B, but I'm really not sure.
  2. jcsd
  3. Apr 6, 2008 #2


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    Not quite. Think of it this way:

    1.Remember the law of conservation of charge. Does this help you eliminate some wrong answers?

    2.Inside the battery must take the charges from their ending point at one end of the battery and move them back to the other end, the starting point, to keep the current going. Thinking in terms of positive charge moving, what way do the charges move around the circuit? What side of the battery is the end point for their "journey?"
  4. Apr 6, 2008 #3
    Well the law of conservation of charge states that charge cannot be created or destroyed in an isolated system, only transferred. So that rules out A and C.

    So then in a closed circuit, the positive charges move outside the battery from the positive terminal, through the load, to the negative terminal. Once they arrive at the negative terminal, the battery has to "pump" them from the negative terminal to the positive terminal in order for this whole process to begin again. If the battery didn't pump the positive charge, then the circuit could not continue to work. Is this the correct thinking?
  5. Apr 6, 2008 #4


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    It seems that you got it. Good job.:smile:
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