MCAT Physics Question 123: Answer and Explanation

Home > MCAT Test > MCAT physics practice tests

Test Information

Question: 123

3. Which of the following statements is inconsistent with the Bohr model of the atom?

  • A. Energy levels of the electron are stable and discrete.
  • B. An electron emits or absorbs radiation only when making a transition from one energy level to another.
  • C. To jump from a lower energy to a higher energy, an electron must absorb a photon of precisely the right frequency such that the photon's energy equals the energy difference between the two orbits.
  • D. To jump from a higher energy to a lower energy, an electron absorbs a photon of a frequency such that the photon's energy is exactly the energy difference between the two orbits.

Correct Answer: D

Explanation:

The Bohr model is based on a set of postulates originally put forward to discuss the behavior of electrons in hydrogen. In summary, these postulates state that the energy levels of the electron are stable and discrete, and they correspond to specific orbits, eliminating choice (A). They also state that an electron emits or absorbs radiation only when making a transition from one energy level to another, eliminating choice (B). Specifically, when an electron jumps from a lower-energy orbit to a higher-energy one, it must absorb a photon of light of precisely the right frequency such that the photon's energy equals the energy difference between the two orbits, eliminating choice (C). When falling from a higher-energy orbit to a lower-energy one, an electron emits a photon of light with a frequency that corresponds to the energy difference between the two orbits, This is the opposite of choice (D), which makes it the right answer.

Previous       Next