For the solidification of pure gold, calculate the critical radius (r) and the activation freeenergy (\Delta G?G). Assume homogeneous nucleation conditions. The values of the latent heat of fusion and the surface free energy are -1.16x109 J/m³ and 0.132 J/m², respectively. The degree of supercooling is 230 K and the melting point of gold is 1064⁰C.