Consider a 1000-W iron whose base plate is made of 0.5-cm-thick aluminum alloy 2024-T6 (r = 2770 kg/m3 and cp = 875 J/kg·°C). The base plate has a surface area of 0.03 m2. Initially, the iron is in thermal equilibrium with the ambient air at 22°C. Assuming 90 percent of the heat generated in the resistance wires is transferred to the plate, determine the minimum time needed for the plate temperature to reach 200°C.
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.
Consider a 1000-W iron whose base plate is made of
0.5-cm-thick aluminum alloy 2024-T6 (r = 2770 kg/m3 and
cp = 875 J/kg·°C). The base plate has a surface area of 0.03 m2.
Initially, the iron is in thermal equilibrium with the ambient air
at 22°C. Assuming 90 percent of the heat generated in the resistance
wires is transferred to the plate, determine the minimum
time needed for the plate temperature to reach 200°C.
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