Entropy Change of Resistor A very large swimming pool filled with water of temperature equal to $20\ \mathrm{^\circ C}$ is heated
  by a resistor with a heating power of $500\ \mathrm{W}$ for $20$ minutes. Assuming the water in the
  pool is not in any contact with anything besides the resistor:
  
  Is the change of entropy of the resistor positive, negative, or zero?


My Attempt 

We know that entropy is given by the formula:

$$\mathrm dS = \frac{q_\text{rev}}{T}$$

My first thought was that since the resistor is giving off heat energy to the water, $q$ must be negative and therefore the entropy change must be negative. However, does the fact that there is a continuous current of electrons passing through the resistor complicate this simple calculation? I am thinking that the current of electrons increase the entropy of the resistor and offsets the decrease in entropy due to heat loss. Am I correct?  


  The answer in the book is that the entropy change is $0$.
Here entropy change will be zero because resistor convert the electrical energy into heating so it take as work not heat so entropy change will be zero