The value of the resistance $R$ in figure is adjusted such that power dissipated in the $2\,\Omega $ resistor is maximum. Then the power dissipated in the $2\,\Omega $ will be ................ $W$
A$72$
B$40$
C$8$
D$32$
Medium
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A$72$
a for max. power in $2\, \Omega, \mathrm{R} \rightarrow 0$
$\mathrm{i}=\frac{12}{2}=6 \mathrm{\,A}$
$P=i^{2} R=36 \times 2=72 \mathrm{\,W}$
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