Coefficient of performance of Carnot
refrigerator $\beta=\frac{\mathrm{Q}_{2}}{\mathrm{W}}=\frac{\mathrm{T}_{2}}{\mathrm{T}_{1}-\mathrm{T}_{2}}$
$\therefore \frac{\mathrm{Q}_{2}}{1}=\frac{260}{315-260}=\frac{260}{55} \Rightarrow$
$\mathrm{Q}_{2}=\frac{260}{55}=4.73 \mathrm{J}$
$\mathrm{Q}_{1}=\mathrm{Q}_{2}+\mathrm{W}=5.73$

$(i)$ What is $W$ along path $ibf$ ?
$(ii)$ If $W = 13$ cal for path $fi$, what is $Q$ for the path $fi$ ?
$(iii)$ Take $E_{int,i} = 10\,\, cal$ then what is $E_{int,f}$ ?
$T_{1}=27^{\circ} C$ [outside fridge]
$T_{2}=-23^{\circ} C$ [inside fridge]

