The specific gravity of tungsten is 13.8 and its atomic weight is 184.0 Assume that there are two free elements per atom. Then the Fermi level or characteristic energy for the crystal in eV will be

A quantity of any substance equal to its molecular weight in grams is a mole of that substance contains the same number of molecules as one mole of any other substance. This Avogadro's number and equals 6.02 x 10²³ molecules per mole. Thus = 9.03 x 10²⁸ electrons/m³ Since for tungsten the atomic and the molecular weights are the same. Therefore for tungsten E_F = 3.64 x 10^-19(η)^2/3 = 3.64 x 10^{- 19}(9.03 x 10²⁸)^2/3 E_F = 7.326 eV.