Heat is transferred at a rate of 2 kW from a hot reservoir at 775 K to a cold reservoir at 300 K. Calculate the rate at which the entropy of the two reservoirs changes. (Round the final answer to six decimal places.)

Respuesta :

Explanation:

The given data is as follows.

           Q = 2 kW,        [tex]T_{1}[/tex] = 775 K

       [tex]T_{2}[/tex] = 300 K

The relation between entropy and heat energy is as follows.

             [tex]\Delta S = \frac{Q}{\Delta T}[/tex]

Therefore, calculate the entropy at each temperature as follows.

                 [tex]S_{1} = \frac{Q}{T_{1}}[/tex]

                            = [tex]\frac{2 kW}{775 K}[/tex]

                            = [tex]2.5 \times 10^{-3}[/tex] kW/K

Also,        [tex]S_{2} = \frac{Q}{T_{2}}[/tex]

                            = [tex]\frac{2 kW}{300 K}[/tex]

                            = [tex]6.6 \times 10^{-3}[/tex] kW/K

Hence, the change in entropy will be calculated as follows.

          [tex]\Delta S = S_{2} - S_{1}[/tex]

                     = [tex](6.6 \times 10^{-3} - 2.5 \times 10^{-3})[/tex] kW/K

                     = [tex]4.1 \times 10^{-3}[/tex] kW/K

or,                 = 0.0041 kW/K

Thus, we can conclude that the rate at which the entropy of the two reservoirs changes is 0.0041 kW/K.