A thin metal plate is insulated on the back and exposed to solar radiation on the front surface. The exposed surface of the plate has an absorptivity of 0.8 for solar radiation. If solar radiation is incident on the plate at a rate of 450 W/m2 and the surrounding air temperature is 25°C, determine the surface temperature of the plate when the heat loss by convection equals the solar energy absorbed by the plate.

A 5-m-internal-diameter spherical tank made of 1.5-cm-thick stainless steel (k = 15 W/m-°C) is used to store iced water at 0°C. The tank is located in a room whose temperature is 30°C. The walls of the room are also at 30°C. The outer surface of the tank is gray (emissivity = 0.9), and heat transfer between the outer surface of the tank and the surroundings is by natural convection and radiation. The convection heat transfer coefficients at the inner and the outer surfaces of the tank are 80 W/m²-°C and 10 W/m²-°C, respectively. Determine the amount of ice at 0°C that melts during a 24-h period. The heat of fusion of water at atmospheric pressure is hfg = 333.7 kJ/kg.\ ANSWER:_____kg

A particular furnace is shaped like a section of a cone. The top surface of the furnace is uniformly heated by a resistance heater. During operation, the top surface is measured to be 800 K and the power supplied to the resistance heater is 1750 W/m². The sidewall of the furnace is perfectly insulated with & = 0.2. If the emissivity of the top and bottom surfaces are ε = 0.5 and ε = 0.7, respectively, determine the temperatures of the sidewall and the bottom surface of the furnace. A₁ A2 A3 →→D₂ = 20 mm D₁ = 40 mm L = 50 mm

Consider a person whose exposed surface area is 1.7 m2, emissivity is 0.7, and surface temperature is 32°C. Determine the rate of heat loss from that person by radiation in a large room having walls at a temperature of (a) 300 K and (b) 280 K.

The horizontal roof of a building has an emittance of 0.9. Air temperature is 1oC on a clear night. Sky acts as a black radiation sink at -60o If the underside of the roof is well insulated, estimate the roof temperature. Assume a convective heat transfer coefficient of 5 W/m2 K.