clear;
clc;
printf("\nEx1.21\n");
//page no.-33
//given
n=4;...........//no. of atoms per unit cell
M=63.5;........//atomic wt. of Ge
N=6.02*10^26;....//avagadro no.
rho=7860;........//density in Kg/m^3
r=0.1278*10^-9;....//atomic radius

a=8^(0.5)*r;.......//lattice constant in m

rho=(n*M)/(N*a^3)......//density in Kg/m^3

printf("\ndensity is 8938.66 Kg/m^3\n");