2

4atoms

4. 2 is correct answer. SOLUTION:- contribution of each atom present at corners of a cube =1/8 total atom present at corners =1/8 *8=1 contribution of one atom present at centre of cube = 1 Hence, number of atom per unit cell in bcc arrangement =1+1=2 ...................................................................

2. 1 atom makes up the corners and 1 occupies the body center.

2

no of particles at corners = 8*(1/8)=1 no of particle at body centre = 1 total particle per unit cell = 1+1 =2