With the aid of a diagram, show how atoms are packed on a face centred cubic lattice. identify the close-packed planes and state their miller indices. [3 marks] (b) the unit cell dimension of face-centred cubic copper is 0.36 nm. calculate the longest wavelength of x-rays that will produce diffraction from the close-packed planes. [3 marks] (c) an incoming x-ray beam given by 3.49x10 (3i +2k)m" is incident on a copper sample. write down the corresponding wave vector for an outgoing beam, diffracted by the close- packed plane from part (a). [4 marks] (d) stating any assumptions that you use, what is the radius of a copper atom? [2 marks] (e) explain why there is no diffraction from x-rays of 0.6 nm. [4 marks] (f) would you expect to see diffraction from nacl (unit cell lattice constant 0.56 nm) using x-rays of wavelength 0.8 nm?