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Heat transfer Page3
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Thermal Expansion: When you heat a substance, the rise in temperature is not the only thing that occurs on the atomic scale. There are other important changes that can arise from the transfer of heat energy, such as thermal expansion and phase change.
The following model shows that a solid responds to heat input by increasing its volume due to increased atomic vibrations. This is thermal expansion.
(Note: the thermal expansion in this model is exaggerated. In reality, it is much smaller.)
Instruction: Click the ‘Heat’ or ‘Cool’ button and observe what happens to the graph on the right.
Pay attention to how the volume of the solid changes. (Note that original surface is marked by the dotted line.)
Now think about the following question:
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<strong><font color="#CCC" size="6">Heat Transfer</font></strong><font color="#CCC" size="6">
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<strong>Q3. Consider two iron rods held at 70 ºC. Iron rod A is 50 m long,
while rod B is 100 m long. If the temperature decreases from 70 ºC to 40
ºC, then:</strong>
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