Physics: Biographies
- James Clerk Maxwell
- James Franck
- James Prescott Joule
- James Rainwater
- James W. Cronin
- Jean Baptiste Biot
- Jean Baptiste Perrin
- Jean Bernard Leon Foucault
- Johann Christian Poggendorff
- Johann von Lamont
- Johannes Diderik van der Waals
- Johannes Georg Bednorz
- Johannes Robert Rydberg
- Johannes Wilhelm Geiger
- John Bardeen
- John Canton
- John Hasbrouck Van Vleck
- John Henry Poynting
- John Tyndall
- John William Strutt Third Baron Rayleigh