The roof of an electrically heated home is 12m long, 16m wide, and 0.50m thick, and is made of a flat layer concrete whose thermal conductivity is k=0.8W/m 2 ·°C. The temperature of the inner and outer surfaces of the roof one night are measured to be 12°C and 1°C, respectively, for a period of 12 hours. Determine a) the rate of heat loss through the roof that night b) the cost of that heat loss to the home owner if the cost of electricity is $0.14/kWh.
Energy transfer
The flow of energy from one region to another region is referred to as energy transfer. Since energy is quantitative; it must be transferred to a body or a material to work or to heat the system.
Molar Specific Heat
Heat capacity is the amount of heat energy absorbed or released by a chemical substance per the change in temperature of that substance. The change in heat is also called enthalpy. The SI unit of heat capacity is Joules per Kelvin, which is (J K-1)
Thermal Properties of Matter
Thermal energy is described as one of the form of heat energy which flows from one body of higher temperature to the other with the lower temperature when these two bodies are placed in contact to each other. Heat is described as the form of energy which is transferred between the two systems or in between the systems and their surrounding by the virtue of difference in temperature. Calorimetry is that branch of science which helps in measuring the changes which are taking place in the heat energy of a given body.
The roof of an electrically heated home is 12m long, 16m wide, and 0.50m
thick, and is made of a flat layer concrete whose thermal
k=0.8W/m 2 ·°C. The temperature of the inner and outer surfaces of the roof
one night are measured to be 12°C and 1°C, respectively, for a period of 12
hours. Determine a) the rate of heat loss through the roof that night b) the
cost of that heat loss to the home owner if the cost of electricity is
$0.14/kWh.
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