In the circuit shown in figure, the $5\,\Omega $ resistance develops $20.00\,cal/s$ due to the current flowing through it. The heat developed in $2\,\Omega $ resistance (in $cal/s$ ) is
AIIMS 2012, Medium
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Let $\mathrm{I}_{1}$ be the current throug $5 \,\Omega$ resistance, $\mathrm{I}_{2}$ through $(6+9) \,\Omega$ resistance. Then as per question,

$\mathrm{I}_{1}^{2} \times 5=20$ or, $\mathrm{I}_{1}=2\, \mathrm{A}$

Potential difference across $C$ and $D=2 \times 5$ $=10 \,\mathrm{V}$

Current $I_{2}=\frac{10}{6+9}=\frac{2}{3}\, A$

Heat produced per second in $2\,\Omega$

$=\mathrm{I}^{2} \mathrm{R}\left(\frac{8}{3}\right)^{2} \times 2=14.2\,\mathrm{cal} / \mathrm{s}$

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