Question about voltage in a battery

  1. Does say a 1.5 volt voltage in a battery mean the change in electric potential as one electron goes from the negative terminus to the positive terminus? Does a larger voltage battery simply mean more kinetic energy through the load (hence more friction/heat)? Or does it have to do with something else? Thanks
     
  2. jcsd
  3. Drakkith

    Staff: Mentor

    Voltage itself is the difference in electric potential between two points. A higher voltage means a larger difference between those two points. If we put a test charge at one of these points, the higher voltage will cause the test charge to accelerate faster and have more energy when it reaches the 2nd point.

    In a real circuit, a battery at 3.0 volts will cause more current to flow than a 1.5 volt battery will, as long as the resistance of the circuit doesn't change. The 3.0 volt battery has the potential to put out more power than the 1.5 volt battery.

    For example, if we have a circuit with a resistive load of 30 ohms, then the 1.5 volt battery will cause 50 milliamps of current to flow and the load will consume 75 milliwatts of power.

    In the same circuit, the 3.0 volt battery will cause 100 milliamps of current to flow and the load will consume 300 milliwatts of power.
     
  4. PhysicoRaj

    PhysicoRaj 437
    Gold Member

    As Drakkith said, more voltage accelerates the electrons to higher velocities (drift velocities to be precise), which means more collisions with the constituent particles and thus more heat dissipation.
     
  5. Because the drift velocity is so small compared to the random movements of the electrons, the number of collisions doesn't change significantly. The amount of energy that the electrons pick up from the field between collisions does.
     
  6. PhysicoRaj

    PhysicoRaj 437
    Gold Member

    You mean the change in K.E between two successive collisions?
     
  7. Yes, I did mean that.
     
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