Scientists beginning with "J"
- Jabłoński, Aleksander — (26.02.1898-9.09.1980) was a Polish physicist and a member of the Polish Academy of Sciences (1956).
- Jacobi, Boris Semyonovich — (21.09.1801-27.02.1874) was a Russian physicist and electrical engineer and a member of the St Petersburg Academy of Sciences (1847).
- Jacquinot, Pierre — (born 18.01.1910) is a French physicist and a member of the Paris Academy of Sciences (1966).
- Jamin, Jules Célestin — (30.05.1818-12.02.1886) was a French physicist and a member of the Paris Academy of Sciences (1868).
- Jánossy, Lajos — (2.03.1912-2.03.1978) was a Hungarian physicist and a member of the Hungarian Academy of Sciences (1950), and its vice-president in 1958-73.
- Javan, Ali — (born 27.12.1926) is an American physicist and a member of the National Academy of Sciences (1974).
- Jeans, James Hopwood — (11.09.1877–16.09.1946) was an English physicist and astrophysicist and a Fellow of the Royal Society (1906).
- Jedlik, Ányos István — (11.01.1800-13.12.1895) was a Hungarian physicist and a member of the Hungarian Academy of Sciences (1858).
- Jensen, Hans — (25.06.1907-11.02.1973) was a German theoretical physicist and a member of the Heidelberg Academy of Sciences (1949).
- Jentschke, Willibald Karl — (born 6.12.1911) is an Austrian physicist.
- Joliot-Curie, Frédéric — (19.03.1900-14.08.1958) was a French physicist and a member of the Paris Academy of Sciences (1943).
- Joliot-Curie, Irène — (12.09.1897 - 17.03.1956) was a French physicist and radiochemist.
- Jolly, Philipp Johann von — (26.09.1809-24.12.1884) was a German experimental physicist.
- Jordan, Pascual — (18.10.1902-31.07.1980) was a German physicist and a member of the Academy of Sciences and Literature in Mainz.
- Josephson, Brian David — (born 4.01.1940) is an English physicist and a Fellow of the Royal Society (1970).
- Jost, Res Wilhelm — (born 10.01.1918) is a Swiss theoretical physicist.
- Joule, James Prescott — (24.12.1818–11.10.1889) was an English physicist, one of the discoverers of the law of conservation of energy, and a Fellow of the Royal Society (1850).
- Jucys, Adolfas Pranovich — (12.09.1904-4.02.1974) was a Soviet theoretical physicist and an academician of the Academy of Sciences of the Lithuanian SSR (1953).