What fraction (n/N) of the lattices sites are vacant at 298 K for a crystal for which the energy required to make a defect is 1 eV (1 eV=1.602xx10^(-19) J ) ?

What fraction (n/N) of the lattices sites are vacant at 298 K for a cr

1.	What fraction (n/N) of the lattices sites are vacant at 298 K for a crystal for which the energy required to make a defect is 1 eV (1 eV=1.602xx10^(-19) J ) ?
Answer» Solution :If `E_upsilon` is the energy REQUIRED to create one VACANT SITE, then by Boltzmann formula `n/N=e^(-E_upsilon //kT)` (k=Boltzmann CONSTANT =`R/N_0`) orIn `n/N=-E_upsilon / "kT"` or log `n/N=- E_upsilon / "2.303 kT"=(1.602xx10^(-19))/(2.303(8.314//6.023xx10^23)xx298)` `=-0.00169185xx10^4 =-16.9185=bar(17).0815` `n/N`=Antilog `bar(17).0815=1.206xx10^(-17)`