Even when shut down after a period of normal use, a large commercial nuclear reactor produces heat at the rate of 130 MW by the radioactive decay of fission products. This causes a rapid increase in temperature if the cooling system fails. (a) Calculate the rate of temperature increase in degrees Celsius per second (°C/s), if the mass of the reactor core is 1.60 x 105 kg and has an average specific heat of 0.0800 kcal/kg-°C. °C/s (b) How long would it take to obtain a temperature increase of 2000°C? (The initial rate of temperature increase would be greater than calculated here, because the heat is concentrated in a smaller mass, but later, the temperature increase would slow because the 5 x 105 kg steel containment vessel would begin to be heated, too.).

(a) Calculate the rate of heat conduction through house walls that are 13.0 cm thick and that have an average thermal conductivity twice that of glass wool. Assume there are no windows or doors. The surface area of the walls is 120m^2 and their inside surface is at 18.0ºC, while their outside surface is at 5.00ºC. (b) How many 1-kW room heaters would be needed to balance the heat transfer due to conduction?

(a)Calculate the rate in watts at which heat transfer through radiation occurs (almost entirely in the infrared) to 4.0 m2 of the Earth's surface at night. Assume the emissivity is 0.95, the temperature of the Earth is 15°C, and that of outer space is 2.7 K. (Include the sign of the heat transfer to 4.0 m2 of the Earth's surface in the value of your answer.)   (b)Compare the intensity of this radiation with that absorbed by the Earth from the Sun during the day. The intensity of the radiation from the Sun averages about 800 W/m2, only half of which is absorbed by the Earth.   (c)What is the maximum magnetic field strength (in µT) in the outgoing radiation, assuming it is a continuous wave?