What feaction (n/N)of the lattice sites are vacent at 298 K for a crystal for which the energy required to make a defect is 1 eV ( 1 eV = 1.602 xx 10^(-19) J) ?

What feaction (n/N)of the lattice sites are vacent at 298 K for a crys

1.	What feaction (n/N)of the lattice sites are vacent at 298 K for a crystal for which the energy required to make a defect is 1 eV ( 1 eV = 1.602 xx 10^(-19) J) ?
Answer» Solution :If ` E_(v) , ` is the energy required to CREATE one vacant site, then by Boltzmann formula . ` n/N =e ^(-E _(v)//KT) `( k = Boltzmann constant =` R/N_(0)` ` or In n/N = - (E_(v))/(kT) ` ` or log n/N = - ( E_(v))/(2.303 kT) = - ( 1.602 xx10^(-19))/(2.303( 8.314//6.023 XX 10^(23)) xx 298)` ` =- 0.00169185 xx 10^(4) = 16.9185= bar(17) . 0815` `n/N = " Antilog" bar(17) .0815 = 1.206 xx 10^(-17)`