Avery thick slab with thermal diffusivity 5.6x10^-6 m^2/s and thermal conductivity 20w/m. k js initially at a uniform temperature of 325 degree c. suddenly, the surface is exposed to a coolant at 15 degree c for which the convection heat transfer coefficient is 100 w/m^2 .k. determine temperatures at the surface and at a depth of 45 mm after 3 min have elapsed. compute and plot temperature histories (0 less than or equal to t less than or equal to 300 s) at x = 0 and x = 45 mm for the following parametric variations: alpha = 5.6 x 10^-7, 5.6 x 10^-6, and 5.6 x 10^-5 m^2/s; and k = 2, 20, and 200 w/m. k.