What do you call the effect of splitting of a spectral line into several components in the presence of a static magnetic field?

Zeeman effect

The correct answer is option 2. Zeeman effect.

The effect of splitting a spectral line into several components in the presence of a static magnetic field is called the Zeeman effect. This phenomenon was first observed by the Dutch physicist Pieter Zeeman in 1896. The Zeeman effect occurs because the energy levels of atoms or molecules are modified in the presence of a magnetic field, causing the spectral lines to split into multiple components. This effect is significant in atomic and molecular spectroscopy and has important applications in areas such as astrophysics and quantum mechanics.