$3\mathrm{.}1.$ Using the data in Table $3\mathrm{.}1$ for copper $(Cu)$ and Aluminum $($Al$),$

$($a$)$ Calculate $D_{Cu}$ and $D_{Al}$ at $600K.$

$($b$)$ At the melting temperature, $T_m,$ calculate $D_{Cu}(T_m=1083C)$ and $D_{AI}$

$(T_m=660C).$

$($c$)$ In comparing diffusion coefficients, which is the more appropriate scaling

factor, $T$ or $T_m?$