= = 6 Consider a large uranium plate of thickness L = 4 cm, thermal conductivity k = 28 W/m. K, and thermal diffusivity a= 12.5X10 m / s that is initially at a uniform temperature of 200C. Heat is generated uniformly in the plate at a constant rate of g = 5X10 W/m3. At time t = 0, one side of the plate is brought into contact with iced water and is maintained at 0C at all times, while the other side is subjected to convection to an environment at To = 30C whith a heat transfer coefficient of h = 45 W/m2 . K. Considering a total of three equally spaced cells in the medium, two at the boundaries and one at the middle, estimate the exposed surface temperature of the plate 10 s after the start of cooling using the Crank-Nicolson method with At = 10s