Calculate the separation of (a) the {123} planes and (b) the {246} planes of an orthorhombic unit cell with a = 0.82nm, b = 0.94nm, and c = 0.75nm. Remember this relationship : (1/d2hkl)= {h2/a2 + k2/b2 + l2/c2 } for orthorhombic lattice (separation planes)