Chapter 15, Problem 30P

To determine

To find : The temperature inside the freezer.

Answer to Problem 30P

  $-13.27°\text{C}$

Explanation of Solution

Given:

  $\text{COP}=7$

  $\begin{array}{c}{T}_H=24°\text{C}\\ =24+273\\ =297\text{K}\end{array}$

Formula used:

The coefficient of performance is,

  $\text{COP}=\frac{T_L}{T_H-T_L}$

Calculation:

Substituting the values,

  $\Rightarrow 7=\frac{T_L}{297-T_L}$

  $\Rightarrow 297\times 7=7T_L+T_L$

  $\Rightarrow 8T_L=297\times 7$

  $\Rightarrow T_L=\frac{297\times 7}{8}$

  $\Rightarrow T_L=\frac{2079}{8}=259.87\text{K}$

  $\Rightarrow T_L=-13.27°\text{C}$

Conclusion :

Thus, the temperature is $-13.27°\text{C}$