Italy in Cosmic Rays and X-ray astronomy) and a number of Italian physicists were forced to leave Italy in the 1930s by Fascist laws against Jews. Other prominent physicists include: Amedeo Avogadro (most noted for his contributions to molecular theory, in particular the Avogadro's law and the Avogadro constant), Evangelista Torricelli (inventor of barometer), Alessandro Volta (inventor of electric battery), Guglielmo Marconi (inventor of radio), Galileo Ferraris and Antonio Pacinotti, pioneers of the induction motor, Alessandro Cruto, pioneer of light bulb and Innocenzo Manzetti, eclectic pioneer of auto and robotics, Ettore Majorana (who discovered the Majorana fermions), Carlo Rubbia (1984 Nobel
Volta potential electrostatic potentials, but instead the difference in Fermi level between the two materials, a difference that is exactly zero at equilibrium. The Volta potential however corresponds to a real electric field in the spaces between and around the two metal objects, a field generated by the accumulation of charges at their surfaces. The total charge formula_2 over each objects' surface depends on the capacitance formula_3 between the two objects, by the relation formula_4 where formula_5 is the Volta potential. It follows therefore that the value of the potential can be measured by varying the capacitance between the materials by a