Atoms

Topics in this chapter

• Bohr Orbits and Quantization
• Hydrogen Energy Transitions
• Hydrogen Spectral Series
• Rutherford Scattering and Stability
• X-Ray Production and Cutoff

Cheat sheet

Practice questions

1. Question 1Q-0FE7CC

   In the Rutherford scattering experiment, what is the relation between the impact parameter $b$ and the scattering angle $\theta$ for a given initial velocity of the $\alpha$-particles?

   1. A.$b$ is directly proportional to $\theta$
   2. B.$b$ is inversely proportional to $\theta$
   3. C.$b$ is directly proportional to $\cot(\theta/2)$
   4. D.$b$ is directly proportional to $\tan(\theta/2)$
   See the answer and solution
2. Question 2Q-937C95

   According to Bohr's quantization condition, the angular momentum of an electron in the $n$-th orbit is equal to:

   1. A.$n \pi / h$
   2. B.$n h / (2\pi)$
   3. C.$2\pi n / h$
   4. D.$h / (n \pi)$
   See the answer and solution
3. Question 3Q-2649C3

   The radius of the inner-most orbit (Bohr radius) of a hydrogen atom is $r_1$. What is the radius of the third orbit ($n=3$)?

   1. A.$3 r_1$
   2. B.$6 r_1$
   3. C.$9 r_1$
   4. D.$27 r_1$
   See the answer and solution
4. Question 4Q-C70967

   What is the ratio of the frequency of revolution of an electron in the $n=2$ Bohr orbit to that in the $n=1$ Bohr orbit of a hydrogen atom?

   1. A.$1:4$
   2. B.$1:8$
   3. C.$8:1$
   4. D.$4:1$
   See the answer and solution
5. Question 5Q-ED58A5

   The total energy of an electron in the ground state of a hydrogen atom is $-13.6\text{ eV}$. What is its kinetic energy in that state?

   1. A.$-13.6\text{ eV}$
   2. B.+13.6\text{ eV}
   3. C.-27.2\text{ eV}
   4. D.+6.8\text{ eV}
   See the answer and solution