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Thermodynamics: Change in Entropy

  • Thread starter djaymilla
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Homework Statement



A 50-ohm resistor carrying a constant current of 1 A is kept at a constant temperature for 27 deg. C by a stream of cooling water. In a time interval of 1s, (a) What is the change in entropy of the resistor? (b) What is the change in entropy of the universe?


Homework Equations



dS = dQ / T
dQ = C dT


The Attempt at a Solution



For part a, I understand that the dQ of the resistor is zero because there is a constant temperature and current.

For part b, I do not understand the relationship between resistance (50 ohm), and dQ. I arrive at the correct answer by plugging in 300K (27 deg C) in for T, and 50 ohm in for dQ, but I would like to understand the correct relationship. Any help?
 

Answers and Replies

  • #2
Mapes
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Power generation (the amount of energy dissipated per second) is calculated as [itex]I^2R[/itex].
 

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