Change in entropy of a resistor

[Elvis 123456789]

Homework Statement

Consider a thermally insulated resistor with resistance R=20 Ω and mass m=5.0 g. The resistor is made of a material with specific heat capacity c=850 J/(g-K) and carries a current of 2.0 A for a time period of 1.0 s.

a) Calculate the increase in the temperature of the resistor if it has initial temperature Tin=20oC. Recall that the power dissipated by a resistor is given by P=I²R.

b) Determine the increase in the resistor's entropy over the period that the current passes through it.

Homework Equations

The Attempt at a Solution

My solution is in the attachment. I just wanted somebody to have a look at it and let me know if it looks okay since I don't feel too sure about it.

 

[gneill]

I note that you used 50g for your mass in the final calculation rather than 5g...

 

[Elvis 123456789]

I note that you used 50g for your mass in the final calculation rather than 5g...

oh woops, the answer should have been ΔS = 0.273 J/K

 

[rude man]

I think part (b) is a trick question but I'm going to wait for other responses if any.
As a hint I don't agree with the computed answer in post 3.

 

[alchemistoff]

Your specific heat capacity is unrealistic. It should be per kilo not gram.

 

[Chestermiller]

Your specific heat capacity is unrealistic. It should be per kilo not gram.

Yes, the approach is correct, but the heat capacity is off by a factor of 1000.