The figure shows three circuits I ,   I I and I I I which are connected to a 3   V battery. If the…

$P=\frac{V^2}{R}$
$P\propto \frac{1}{R}$
$R_{eq}$ for $\left(I\right)$ circuit by balanced Wheatstone bridge
 $R_1=1 \mathrm{\Omega }$

$R_{eq }$for circuit $\left(II\right)$ by parallel combination
$\frac{1}{R_2}=\frac{1}{2}+ \frac{1}{2}+\frac{1}{1}$

 $R_2=\frac{1}{2}$

$R_{eq}$for circuit $\left(III\right)$ by parallel and series combination
$R_3=1+\frac{1}{{\displaystyle \frac{1}{2}}+{\displaystyle \frac{1}{2}}}$
$R_3=2$

so,$P_2>P_1>P_3$.