A one-dimensional plane wall of thickness 2L = 100 mm experiences uniform thermal energy generation of q = 1000 W/m³ and is convectively cooled at x = ± 50 mm by an ambient fluid characterized by T_∞ = 20°C. If the steady-state temperature distribution within the wall is T(x) = a(L² – x²) + b where a = 10°C/m² and b = 30°C, what is the thermal conductivity of the wall? What is the value of the convection heat transfer coefficient, h?