$4.)$ Using the data For the grain growth in Cu$-307$n brass, please do the following:

a$.)$ calculate the activation energy $(Q)$ and the pre$-$factor, $K_0$ from this data.

b$.)$ Estimate the grain size of the brass after $110$ minutes at $550C.$

c$.)$ estimate the grain growth exponent, $n,$ for each temperature. Is the value close to its ideal value?

$($IIints: please use $D_0=0\mathrm{.}001cm$ for your calculations. I would recommend converting everything to cm and seconds for parts a and b $.$ Also, use either the $60$ minutes or $90$ minutes data for determining Q and Ko $.$