Michigan Test for Teacher Certification (MTTC) Secondary Integrated Science Practice test

Which quantum number relates to the orientation of light emission in a magnetic field?

1. Principal quantum number

2. Azimuthal quantum number

3. Magnetic quantum number

4. Spin quantum number

The correct answer is: Magnetic quantum number

The magnetic quantum number is directly related to the orientation of light emission in a magnetic field. It defines the specific orientation of an orbital in relation to the three-dimensional coordinate system, which includes the effects of an external magnetic field. When light interacts with atoms in a magnetic field, the energy levels of the electrons are influenced by the orientation of their respective orbitals, and this leads to phenomena such as the Zeeman effect, where spectral lines split into multiple components. This splitting is directly associated with the values that the magnetic quantum number can take, indicating how many different orientations exist for a given state. In contrast, the principal quantum number pertains to the overall energy level and size of the electron cloud, the azimuthal quantum number relates to the shape of the orbital, and the spin quantum number describes the intrinsic spin of the electron. These other quantum numbers do not provide information about the orientation of light emission in a magnetic field.