There is an example in the textbook to show the change of entropy. A resistor being held at fixed temperature of 300K. 10 amp current passes through the resistor for 300 seconds. The change in entropy of the resistor is ZERO. The reason written in the book reads since the temperature doesn't change, the state doesn't change, so the entropy doesn't change. I am very confuse about this statement ... if it is asking the change of entropy of gas, it is easy to understand, but now it is asking something like resistor, what does it mean by 'change of state'? Does it mean change of energy? If so, the resistor will absorb energy from the current and change some of them to heat, so the entropy of the resistor so be [tex]\Delta Q/T[/tex], [tex]\Delta Q[/tex] is heat released and T is temperature.