Determining greater change in entropy!


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Regina Chi 2K
Posts: 51
Joined: Fri Sep 26, 2014 2:02 pm

Determining greater change in entropy!

Postby Regina Chi 2K » Fri Feb 06, 2015 5:24 pm

This is actually a question on the 2010 midterm practice exam. It is part B of the problem 4B. I also realize that this is a homework problem from chapter eight. It asks us which (house exterior or interior) has a greater change in entropy. However, they also mentioned that the temperature stays the same even though heat went into the house from the outside. They make the statement T (interior) > T (exterior) and therefore change in entropy for the interior of the house must be less than change in entropy of the outside of the house. I understand how this works because of the equation: change in entropy = q (heat) / T (temperature). However, how did they come up with the statement T (interior) > T (exterior)? Should we assume that the interior of the house would naturally be warmer than the exterior of the house?

Kayla Denton 1A
Posts: 106
Joined: Fri Sep 26, 2014 2:02 pm

Re: Determining greater change in entropy!

Postby Kayla Denton 1A » Fri Feb 06, 2015 7:01 pm

The way I see it is pretty simplistic—the question initially says that the pump "extracts heat from the COLD outdoors and releases it into the WARM interior." It seems to specify an initial temperature difference!

Satvir Saggi 1I
Posts: 22
Joined: Fri Sep 26, 2014 2:02 pm

Re: Determining greater change in entropy!

Postby Satvir Saggi 1I » Fri Feb 06, 2015 7:03 pm

The question states that "the heat pump heats a house in winter by extracting heat from the cold outdoors and releasing it into the warm interior. Therefore, based off the statement, we can deduce that the temperature of the interior is greater than the temperature of the exterior.


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