If the period of rotation of electron in the Bohr hydrogen atom is 4.10 fs,which Bohr orbit does the electron occupy?
A)first
B)second
C)third
D)fourth
E)fifth

Question

Quizplus · Accepted Answer

The period of rotation of an electron in a Bohr orbit is given by $T_n = \frac{2\pi n^3 h}{Zke^2}$, where $n$ is the principal quantum number (or the orbit number), $h$ is Planck's constant, $Z$ is the atomic number (which is 1 for hydrogen), $k$ is Coulomb's constant, and $e$ is the charge of an electron. Given the period $T = 4.10$ fs, we can solve for $n$ using the formula. The calculation shows that the electron occupies the third orbit.

If the Period of Rotation of Electron in the Bohr