In the adjoining circuit, the galvanometer $G$ shows zero deflection. If the batteries $A$ and $B$ have negligible internal resistance, the value of the resistor $R$ will be .............. $\Omega$
A$500$
B$1000$
C$200$
D$100$
Medium
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D$100$
d Galvanometer will show zero deflection, if $\mathrm{I}_{1}=\mathrm{I}_{2}$
$\therefore $ $\frac{12}{500+R}=\frac{2}{R}$
or $\mathrm{R}=100\, \Omega$
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