A2L Item 092

• Description: Identify the correct definition of heat.
• Goal: Hone the concept of heat and distinguish from internal energy.
• Source: UMPERG-ctqpe191
• Keywords: Heat, Thermodynamics

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The question for students:

Which of the following phrases best describes heat?

1. The total energy possessed by a body.
2. The flow of temperature to or from a body.
3. The amount of energy dissipated by friction.
4. The total energy flowing between two bodies at different temperatures.
5. The useful work that could be extracted from a body.

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Commentary for teachers:

Answer

(4) Many students are confused about what heat is because the term is not used consistently. ‘Heat’ is usually used to refer to the thermal energy that flows into or out of a body. So ‘heat’ is not equivalent to ‘energy’ and it is inappropriate to refer to the heat possessed by a body. Unfortunately, the redundant phrase ‘heat flow’ is often used in texts. In addition, students frequently attribute any loss of coherent energy to friction, which has converted the energy into ‘heat’.

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