Element X has an FCC crystal structure with lattice parameter a = 3.6 . The self-diffusion coefficient of X is given as D= ) = 0.2 exp 197100 RT cm .s-7, where R= 8.314 J mol-1. K-1 Assume X self-diffusion is through the vacancy-mechanism and the atom hop rate is given by 6D T= d2 where d is the atom hop distance. Calculate the average atom-X hop rate at 675 K