Calculate the time required for the temperature of the cube to fall to 300 °C.

Take the thermal conductivity, specific heat capacity and density to be 390 W/(m.K), 410 J/(kg.K) and 7500 kg/m^3 respectively and the surface heat-transfer coefficient to be 5 W/(m^2.K) for the five exposed faces of the cube.

Anye help would be greatly appreciated.