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I am confused as it is written that sometimes it is true to say that heat given to a body can decrease its temperature.

Eagle
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Ram Mohan
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    See https://physics.stackexchange.com/questions/232990/are-there-any-known-negative-heat-capacities (another example of a negative heat capacity is black holes) – Anders Sandberg Apr 29 '19 at 10:28
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    Is it saying that it is true or asking if it is possible? I don’t read it as a statement. Are you quoting this exactly? – Bob D Apr 29 '19 at 10:56

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It is my understanding that heat capacity and specific heat can never be negative. Now, if the question was is it possible for a system to undergo a process in which heat is added and its temperature decreases, my answer would be yes. For this to happen, the work done by a closed system would need to exceed the heat added to the system so that it's internal energy decreases according to the first law

$$\Delta U=Q-W$$

and if a change in internal energy results in a temperature decrease. That would be the case if the system was an ideal gas, because for an ideal gas, any process

$$\Delta U=C_{v}\Delta T$$.

Hope this helps.

Bob D
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  • I'd be interested in the reason for the down vote. I don't mind a down vote if I can learn something from it. – Bob D Apr 29 '19 at 16:47