Wilhelm Conrad Röntgen (27.03.1845 - 10.02.1923) was a German experimental physicist and a corresponding member of the Berlin Academy of Sciences (1896).
Ernest Rutherford (30.08.1871-19.10.1937) — an English physicist, the founder of nuclear physics, a Fellow of the Royal Society (1903) and its president in 1925-30.
Petr Alexandrovich Ryazin (born 20.10.1906) is a Soviet physicist, an academician of the Academy of Sciences of the Kirghiz SSR (1960) and its vice-president in 1960–65.
Erik Gustav Rydberg (17.11.1902-2.01.1980) was a Swedish physicist and a member of the Royal Swedish Academy of Sciences, and in 1959 —72 its secretary.
Johannes Robert Rydberg (8.11.1854 —28.12.1919) was a Swedish physicist and mathematician and a member of the Royal Swedish Academy of Sciences (1919).