Problema 2. A spherical thin walled metallic container is used to store liquid nitrogen al a temperature of -193C. The container diameter is 0.5 m and it is covered with two insulating materials each of thickness 25 mm and the outer surface is exposed to ambient air at 303 K. The termal conductivities of the first and second insulating layers are 0.042 W/mK and 0.0017 W/mK respectively. If outer heat transfer coefficient is 20 W/mK and the latent heat of vaporization of liquid nitrogen is 2 x109 kJ/kg Determine the rate of vaporization of liquid nitrogen per hour (Valor 5 dcimos) selante