A long cylindrical heater 25 mm in diameter is maintained at 627°C and has a surface emissivity of 0.8. The heater is located in a large room whose walls are at 27°C. How much will the radiant heat...

A long cylindrical heater 25 mm in diameter is maintained at 627°C and has a surface emissivity of 0.8. The heater is located in a large room whose walls are at 27°C. How much will the radiant heat transfer from the heater be reduced if it is surrounded by a 0.2 m diameter radiation shield having an emissivity of 0.2. What is the temperature of the shield?