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

Calculating Current given the number of electrons and positive ions

  1. Feb 16, 2009 #1
    1. The problem statement, all variables and given/known data

    In a fluorescent tube of diameter 3 cm, 10 *1018 electrons and 2.5 * 1018 positive ions (with a charge of +e) flow through a cross-sectional area each second. What is the current in the tube?

    2. Relevant equations
    Current is I = (delta Q)/(deta T)

    3. The attempt at a solution

    delta t is given as 1 second, but how do u calculate the change in charge given this information?
  2. jcsd
  3. Feb 16, 2009 #2


    User Avatar
    Homework Helper

    Use the charge on the electron. Note that the positive ions will go the opposite way to the electrons, so you must add the two currents.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook