1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
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: Seemingly Simple - How Many Orbits? (Rotational Kinematics)

  1. Oct 22, 2006 #1
    This is the latest question I've been stuck on.

    The Bohr model of the hydrogen atom pictures the electron as a tiny particle moving in a circular orbit about a stationary proton. In the n=2 orbit, the distance from the proton to the electron is 21.16e-11 m , and the linear speed of the electron is 1.09e6 m/s.

    How many orbits about the proton does it make each second?

    Now, I found the angular velocity of the electron and got that correct: 5.15e15 rad/s. Now, to find the # of orbits, shouldn't I just convert to revolutions per second, which is 8.09e15 rev/s? The computer tells me I'm wrong, however, but I don't know what I could do differently.

    Again, I appreciate your time!
  2. jcsd
  3. Oct 22, 2006 #2


    User Avatar
    Science Advisor
    Homework Helper

    I promise you that it is impossible to do more full revolutions than radians in the same amount of time. Your angular velocity looks good; your conversion does not.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook