Calculate the homogeneous nucleation rate in liquid copper at undercoolings of 180, 200, and 220 C. Use the following data for Cu: melting temperature: 1356K, latent heat of fusion: 1.88 x 10'J/m, surface free energy: 0.177 J/m, attempt frequency: 10'5", # atoms on nucleus surface: 6 x 1028 atoms/m (assume this constant applies to the number of atoms per unit volume in the liquid phase). 4. For the transformation of Cu described in question 1, if nucleation were to instead occur on an internal structural inhomogeneity with a wetting angle of 450, what would be the required undercooling to maintain an identical nucleation rate to solid Cu homogeneously nucleating at an undercooling of 200 "C? Assume the shape factor scales with the wetting angle (0) according to: 0.25/(2 + cos)(l-cosol