Bohr magneton

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In atomic physics, the Bohr magneton (symbol ) is named after the physicist Niels Bohr. It is a physical constant of magnetic moment, defined in SI units by

and in Gaussian centimeter-gram-second units by


is the elementary charge,
is the reduced Planck's constant,
is the electron rest mass
is the speed of light.

In the SI system of units its value is

= 9.274 009 49(80) × 10-24 JT-1.

In the eV system of units its value is

= 5.7883 × 10-5 eV•T-1.

In the CGS system of units its value is

= 0.927 × 10-20 ErgOe-1 [1]

The Bohr magneton is the natural unit for expressing the electron magnetic dipole moment in the hydrogen atom. It was first calculated by Romanian physicist Stefan Procopiu around 1910 and in some Romanian literature is called the Bohr-Procopiu Magneton. An electron has an intrinsic magnetic dipole moment of approximately one Bohr magneton.[2]


  1. Robert C. O'Handley (2000). Modern magnetic materials: principles and applications. John Wiley & Sons. ISBN 0-471-15566-7 page 83
  2. A. Mahajan and A. Rangwala. Electricity and Magnetism, p. 419 (1989). Via Google Books.

See also

ca:Magnetó de Bohr cs:Bohrův magneton de:Bohrsches Magneton it:Magnetone di Bohr sk:Bohrov magnetón sr:Боров магнетон sv:Bohrmagnetonen uk:Магнетон Бора