Roentgen, Wilhelm Conrad (born March 27, 1845, Lennep, Prussia, d. Feb. 10, 1923, Munich) German physicist who was a recipient of the first Nobel Prize for Physics, in 1901, for his discovery of X rays, which heralded the age of modern physics and revolutionized diagnostic medicine.
Roentgen studied at the Polytechnic in Zurich and then was a professor of physics at the universities of Strasbourg (1876-79), Giessen (1879-88), Wurzburg(1888-1900), and Munch (1900-20). His research also included work on elasticity, the capillary action of fluids, specific heats of gases, condition of heat in crystals, absorption of heat by gases, and piezoelectricity.
In 1895, while experimenting with electric current flow in a partially evacuated glass tube (cathode-ray tube), Rontgen observed that a nearby piece of barium Platinocyanide gave off light when the tube was in operation.