Ștefan Procopiu

Ștefan Procopiu (January 19, 1890 – August 22, 1972) was a Romanian physicist, professor and inventor.

Procopiu dedicated himself to science and research from the time he was still a student. The first remarkable results of his research were published in 1913, within the famous paper “Determining the Molecular Magnetic Moment” by M. Planck’s Quantum Theory. After studying Planck’s quantum theory and Langevin’s magnetism theory, Procopiu was the first to establish in the whole world the value of the molecular magnetic moment also named the theoretic magneton. It is recognized that Ştefan Procopiu calculated the value of the theoretic magneton two years before prof. A. Bohr of Denmark. In the Romanian specialized literature, this discovery is known as the Bohr-Procopiu magneton. Continuing his studies, in 1954 he established a method for the experimental determination of the magneton, which he improved in 1963.

In 1916 he invented a device for locating and establishing the depth of bullets in the bodies of the wounded soldiers.

In 1921, Procopiu discovered and analyzed in the Physics Laboratory of Sorbonne University a new optical phenomenon which consisted in the longitudinal depolarization of light by suspensions and colloids. In 1930, the occurrence was designated as "Procopiu Phenomenon" by prof. Augustin Boutaric.

In 1930, studying the Barkhausen effect, Ștefan Procopiu discovered a circular effect of magnetic discontinuity. In 1951, this effect was named "Procopiu Effect". This discovery had important applications in the development of the memory of computers.

Earth’s magnetism was a continuous concern of Ștefan Procopiu, For 25 years he studied this phenomenon in Romania and developed the magnetic maps of the country. He also identified the magnetic anomaly located on the Iași-Botoșani line.

In 1947, Procopiu identified a variation of the Earth's magnetic field, with a periodicity of approximately 500 years, indicating that, starting 1932 Earth's magnetic moment increases from the equator to the poles.

1.       The discovery that had important applications in the development of the memory of computers is called

a)       Magneton

b)       longitudinal depolarization of light

c)       circular effect of magnetic discontinuity

2.       The “Procopiu phenomenon” is:

a)       longitudinal depolarization of light

b)       the periodicity of the Earth’s magnetic field

c)       the circular effect of magnetic discontinuity

3.       The device for locating and establishing the depth of bullets in the bodies of the wounded soldiers was invented in:

a)       1930

b)       1913

c)       1916.