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Homework Help: Magnitude of the current flowing around the nucleus in the Bohr mode

  1. Feb 13, 2014 #1
    magnitude of the "current" flowing around the nucleus in the Bohr mode

    1. The problem statement, all variables and given/known data
    According to the Bohr model, a hydrogen atom in its lowest energy state has a nucleus consisting of a single proton, which is orbited by a single electron. The speed of the electron is 2.19×106 m/s and the radius of its orbit (the "Bohr radiuis") is 5.29×10−11 m. What is the magnitude of the "current" flowing around the nucleus in the Bohr model?


    2. Relevant equations

    equation used : I=nAvq ( i was surfing internet and found this equation, i couldn't find equation from the book)

    2nd try: equation : I = e*w, where e is elementary charge and w is revs/s.

    3rd try: J=I/A J is magnitude of current density.

    3. The attempt at a solution
    1st: I= 1*2pi(5.29e-11)^2(2.19e6)(-1.6e-19)
    I= -6.16e-30 A seems very wrong.

    e = 1.6022E-19
    w = v/(2pi*r)
    I = 9.46518E-4 A ( i found this on yahoo answers, but it wasn't right, and i never seen that equation before.)

    3rd: I don't know how to find the current if i use this equation. Please help.
  2. jcsd
  3. Feb 13, 2014 #2


    Staff: Mentor

    What is the definition of the ampere? It should have something to do with columbs per second.

    Now as the electron orbits the hydrogen atom at the speed you gave it will orbit how many times in one second?

    Does that help?
  4. Feb 13, 2014 #3
    Oh, so 2pi(5.29e-11)/2.19e6 = 1.518e-16 s for 1 rev. 1/1.518e-16 = 6.588e15 rev. and do i just multiply by the charge? I=q*w
    -1.6e-19(6.588e15)= .00105 is that right? I'm not sure because i didn't see that equation in the book.
    Thanks. And since it's magnitude it should be negative right?
    Last edited: Feb 13, 2014
  5. Feb 14, 2014 #4


    Staff: Mentor

    velocity * 1 second =distance traveled in 1 second

    distance / (2 * pi * radius) ==> # of revs in 1 second

    # of revs ==> # electrons passing by in 1 second

    # electrons / 6.241×10E18 ==> # colombs in 1 second ==> amperes

    in your example you're squaring the r value why?
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