Question

3. What is Normal Zeema effect? On the basis of quantum theory, explain the effect of magnetic field on the energy levels of the atom.

Answer 1

Answer:

The Zeeman effect, named after the Dutch physicist Pieter Zeeman, is the effect of splitting of a spectral line into several components in the presence of a static magnetic field. It is analogous to the Stark effect, the splitting of a spectral line into several components in the presence of an electric field.

A normal Zeeman effect is observed when a spectral line of an atom splits into three lines under a magnetic field. An anomalous Zeeman effect is observed if the spectral line splits into more than three lines. Astronomers can use the Zeeman effect to measure magnetic fields of stars.

The magnetic quantum number (symbol ml) is one of four quantum numbers in atomic physics. The set is: principal quantum number, azimuthal quantum number, magnetic quantum number, and spin quantum number. Together, they describe the unique quantum state of an electron.  (360 degrees in radians) represent the same position in space.

Answer 2

Answer:

Normal Zeeman effect

In an experiment performed by the Dutch physicist Peter Zeeman in 1896, it was observed that each spectral line in the excitation spectrum for an atom placed in a magnetic field split into number of additional lines. Furthermore, the difference in energy between the new lines and the original line was found to be directly proportional to the strength of the external field. This effect came to be known as Zeeman effect. It could only be explained using quantum mechanics which says that the orbital angular momentum is quantized both in magnitude and direction:

Explanation:

The explanation of the spectrum of the hydrogen atom was a leap forward, made possible by quantum mechanics. However, the spectra of other elements were not yet explained. Moreover some subtle effects were observed already at the beginning of the 20th century, for which no explanation existed. Zeeman investigated spectral lines in a magnetic field and observed some interesting phenomena.

Magnetic effects and quantum mechanics

In quantum mechanics shifts of energy levels are not explained by referring to oscillatory motion of electrons (Lorentz model), but rather in terms of change of energy (or potential). The magnetic interaction energy of a magnetic dipole in a magnetic field can be added to the energy of the system. The magnetic dipole moment may be described in a semi classical way by relating it to the (quantized) orbital angular momentum vector.