The temperature inside a refrigerator is $t_2{}^{0}C$and the room temperature is $t_1{}^{0}C$. The amount of heat delivered to the room for each joule of electrical energy consumed ideally will be

For a refrigerator, we know that $\frac{Q_1}{W}=\frac{Q_1}{Q_1-Q_2}=\frac{T_1}{T_1-T_2}$where,

$Q_1=$amount of heat delivered to the room

$W=$electrical energy consumed

$T_1=$room temperature $=t_1+273$

$T_2=$temperature of sink $=t_2+273$

$\therefore \frac{Q_1}{1}=\frac{t_1+273}{t_1+273-\left(t_2+273\right)}\Rightarrow Q_1=\frac{t_1+273}{t_1-t_2}$