Consider a cubic block whose sides are $5$ cm long. The block is initialy at $20C$ and is made of granite $(k=2\mathrm{.}5\frac{W}{m}.C$ and $($:$=1\mathrm{.}15{10}^{-6}\frac{m^2}{s}\}.$ Now block is exposed to hot gases at $500C$ in a furnace on all of its surfaces with a heat transfer coefficient of $40\frac{W}{m^2}$C$.$ Determine the center temperature of cubic block after $10,20$ and $60$ min.