Friedrich Hasenöhrl (30.11.1874-7.10.1915) was an Austrian theoretical physicist and a corresponding member of the Austrian Academy of Sciences. He was born in Vienna. He graduated from the University of Vienna (1897). In 1905-07 he was professor at the Higher Technical School in Vienna, and from 1907 professor of theoretical physics at the University of Vienna.
His work was in the fields of kinetic theory, thermodynamics, statistical mechanics, electrodynamics, the optics of moving bodies, relativity and quantum theory. In 1904 — 05 he derived a formula for the electromagnetic mass and a formula for the relation between mass and energy, which differed from Einstein's by a factor of 4/3; he was the first to attempt an interpretation of the Balmer series on a quantum basis.