Cooling a Steel Rod. A long steel rod $0\mathrm{.}305m$ in diameter is initially at a temperature of $588K.$ It is immersed in an oil bath maintained at $311K.$ The surface convective coefficient is $125\frac{W}{m^2.K}.$ Calculate the temperature at the center of the rod after $1h.$ The average physical properties of the steel are $k=38\frac{W}{m.K}$ and $=0\mathrm{.}0381\frac{m^2}{h}.$