A sphere of radius 0.500 m, temperature 27.0°C, and emissivity 0.850 is located in an environment of temperature 77.0°C. At what rate does the sphere (a) emit and (b) absorb thermal radiation? (c) What is the sphere's net rate of energy exchange?

The exterior walls of a house have a total area of 194 m2 and are at 12.4°C and the surrounding air is at 7.4° C. Find the rate of convective cooling of the walls, assuming a convection coefficient of 2.9 W/(m2·°C). Since you're looking for the rate of cooling, your answer should be entered as positive.

Suppose you stand with one foot on ceramic flooring and one foot on a wool carpet, making contact over an area of 80 cm² with each foot. Both the ceramic and the carpet are 1.9 cm thick and are 8 deg C on their bottom sides. At what rate must heat transfer occur from each foot to keep the top of the ceramic and carpet at 35 deg C? The thermal conductivity of carpet k =0.04 J/(s m °C) The thermal conductivity of ceramic k =0.84 J/(s m º°C) Rate of Heat Transfer of Wool = 0.04547 t W Rate of Heat Transfer of Cermaic Qc 0.5657 t ✓ W No, that's not the correct answer.

Suppose you walk into a sauna that has an ambient temperature of 65.0°C. (a) Calculate the rate of heat transfer to you by radiation given your skin temperature is 37.0°C, the emissivity of skin is 0.98, and the surface area of your body is 1.50 m². (b) If all other forms of heat transfer are balanced (the net heat transfer is zero), at what rate will your body temperature increase if your mass is 60.0 kg? O A. None of the options provided is correct. O B. a) 1.89 kW, b) 137.7°C/h O C. a) 2 kW, b) 10°C/h ○ D. a) 318.5 W, b) 5.46 °C/h ○ E. a) 5.46 W, b) 318.5 °C/h