- #1
annaphys
- 69
- 1
Hello,
If two bodies, who say start with ##T_{cold}=T_c## and ##T_{hot}=T_h## and then they are brought in contact with one another and then after some time they both have the same temperature. What would be the entropy of the entire system?
Also another quick question, I've looked at some example problems of entropy and I would like to know why sometimes the entropy can be negative? For example, 1000J of heat is used into 470J of work when ##T_1 = 540K## and ##T_2=300K##.
##\triangle S = \frac{-1000J}{540K} = -1.85J/K## Why do we have a minus sign?
If two bodies, who say start with ##T_{cold}=T_c## and ##T_{hot}=T_h## and then they are brought in contact with one another and then after some time they both have the same temperature. What would be the entropy of the entire system?
Also another quick question, I've looked at some example problems of entropy and I would like to know why sometimes the entropy can be negative? For example, 1000J of heat is used into 470J of work when ##T_1 = 540K## and ##T_2=300K##.
##\triangle S = \frac{-1000J}{540K} = -1.85J/K## Why do we have a minus sign?