A spherical vessel, 3.0 m in diameter (and negligible wall thickness), is used for storing a fluid at a temperature of 0°C. The vessel is covered with a 5.0-cm-thick layer of an insulation (k = 0.20 W/m·K). The surrounding air is at 22°C. The inside and outside heat transfer coefficients are 40 and 10 W/m²·K, respectively. Calculate

(a) All thermal resistances, in K/W,

(b) The steady rate of heat transfer,

(c) The temperature difference across the insulation layer.