Entropy of running water around a resistor


by bmarson123
Tags: entropy, resistor, running water
bmarson123
bmarson123 is offline
#1
Aug27-11, 08:22 AM
P: 24
1. The problem statement, all variables and given/known data
An electric current of 10A runs for 1 minute through a 20 ohm Resistor which is maintained at 10 degC by being immersed in running water. What are the entropy changes in a) the resistor b) the running water c) the universe


2. Relevant equations

P = I2R

dS = dQ/T

3. The attempt at a solution

For a) there is no change in the entropy as it is work done by the resistor, not heat.

b) I've calculated P = 2000W = 2000J

The problem I'm having is formulating the path between the initial and final states of the system because of the constant temperature. I'm also not sure if I'm using the right equation?

c) This will be the same as the answer for b) I think.
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bmarson123
bmarson123 is offline
#2
Aug27-11, 08:45 AM
P: 24
Figured it out!

Forgot to convert the temperature to kelvin and then got everything written down in a mess!


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