In an electrically heated home, the temperature of the ground in contact with a concrete basement wall is 12.9 C. The temperature at the inside surface of the wall is 20.2 C. The wall is 0.13 m thick and has an area of 7.5 m2. Assume that one kilowatt hour of electrical energy costs $0.10. How many hours are required for one dollar's worth of energy to be conducted through the wall? Number UnitsIn an aluminum pot, 0.951 kg of water at 100 C boils away in four minutes. The bottom of the pot is 3.04 x 10'3 m thick and has a surface area of 0.0163 m2. To prevent the water from boiling too rapidly, a stainless steel plate has been placed between the pot and the heating element. The plate is 1.08 X 10'3 m thick, and its area matches that of the pot. Assuming that heat is conducted into the water only through the bottom of the pot, nd the temperature in degrees Celsius at the steel surface in contact with the heating element. Number n Units V Multiple-Concept Example 8 reviews the approach that is used in problems such as this. A person eats a dessert that contains 250 Calories. (This "Calorie" unit, with a capital C, is the one used by nutritionists; 1 Calorie = 4186 J. See Section 12.7.) The skin temperature of the person is 38 C and that of her environment is 15 C. The emissivity of her skin is 0.72 and its surface area is 1.2 m2. How many hours would it take her to emit a net radiant energy from her bodythat is equal to the energy contained in this dessert? \fA solid sphere has a temperature 01'630 K. The sphere is melted down and recast into a cube that has the same emissivity and emits the same radiant power as the sphere. What is the cube's temperature in kelvins? Number n Units V