The concept of thermionic emission is the basis of modern X-ray tubes, which are the workhorse of a medical X-ray image. In this process, a filament (a piece of metal in a vacuum) is heated by the application of electrical current. The heat (energy) is transferred to the 'free' electrons of the metal, which allows some electrons to escape from the surface. After a short period of operation, the filament has lost enough electrons to give it an overall charge of 1.250 10-6 C. How many electrons, ne, has the filament lost? If the filament is 1.10 g of tungsten, what fraction of electrons, ef, does this represent? (HINT: The atomic number of tungsten is 74.0, the atomic weight is 183.8 g/mol, and Avogadro's constant equals 6.02 x 1023 atoms/mol.) ne = 7.812 x1012 ef= -11 1.299x10 Incorrect