Question

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 9.50×10−79.50×10−7 C.

How many electrons, ?ene, has the filament lost? If the filament is 2.452.45 g of tungsten, what fraction of electrons, efef, does this represent? (HINT: The atomic number of tungsten is 74.074.0, the atomic weight is 183.8183.8 g/mol, and Avogadro's constant equals 6.02×10236.02×1023 atoms/mol.)

Answer 1