Arrange simple cube,body-centred cube,face-centred cube and hexagonal close packing increasing order of packing efficiency.

In a simple cubic crystal packing efficiency is ____ .

Define face centred cubic and body centred cubic unit cell.

If 'a' stands for the edge length of the cubic systems, simple cubic, body centred cubic and face centred cubic, then the ratio of radii of the spheres in these systems will be respectively,

Describe the characteristics of hexagonal close packed structure giving examples.

What do you understand by close packing of spheres? Discuss briefly hexagonal close packing and cubic close packing of spheres.

Calculate the total number of voids present in the unit cell of a hexagonal close packing crystal.