The power dissipated in the circuit shown in the figure is $30\, Watts$. The value of $R$ is ............. $\Omega$
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Power dissipated in $5\, \Omega$
${=\mathrm{i}^{2} \mathrm{R}} $
${=(2)^{2} \times 5=20 \mathrm{\,W}}$
$\therefore $ Power dissipated in $\mathrm{R}=30-20$
$=10 \mathrm{\,Watt}$
$\therefore \quad 10=\frac{(10)^{2}}{\mathrm{R}}$
$\mathrm{R}=\frac{100}{10}=10\, \Omega$
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