A small spherical droplet $(1mg)$ of liquid $Cu$ is cooled until it solidifies. Calculate

the critical undercooling $T^{**}$ required to form one single critical nucleus,

homogeneously. Note that for $Cu,T_m=1083C,$ surface tension ${}_{SL}=200\frac{\text{e}\text{r}\text{g}\text{s}}{c{m}^2},$

density of liquid $Cu=10\frac{g}{c{m}^3},$ latent heat of melting $H_m=50\frac{\text{c}\text{a}\text{l}}{g},$ and atomic

volume of solid $Cu$ is $1\mathrm{.}18{10}^{-29}{m}^3.$ In addition, you can assume the density of

nuclei sites within the liquid droplet is $\frac{{10}^{20}}{c}{m}^3.$ Compare your solution obtained

using both the Volmer$-$Weber and Becker$-$D$$ring approaches.