# Variable vs Constant Specific Heat



## BuffaloWings (Apr 28, 2020)

How should someone decide when looking at a problem on the PE Exam if they should solve the problem using variable or constant specific heats. 
 

There have been some practice problems where they have not identified a Cold Air Ideal or Standard assumptions and I used the variable specific heat method but calculated the wrong answer because they used constant specific heat.


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## Slay the P.E. (Apr 28, 2020)

See this post 

http://engineerboards.com/topic/34191-pe-thermal-and-fluids-system-study-pal-october-2019/?do=findComment&amp;comment=7569055


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## Slay the P.E. (Apr 28, 2020)

BuffaloWings said:


> There have been some practice problems where they have not identified a Cold Air Ideal or Standard assumptions and I used the variable specific heat method but calculated the wrong answer because they used constant specific heat.


That would be a poorly crafted problem. Can you share the problem statement (don't reveal the source)?


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