The resistance of a wire is $R$. It is bent at the middle by $180^{\circ}$ and both the ends are twisted together to make a shorter wire. The resistance of the new wire is
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(c)
Resistance of wire $(R)=\rho \frac{l}{A}$ If wire is bent in the middle then $l^{\prime}=\frac{l}{2}, A^{\prime}=2 A$
$\therefore$ New resistance, $R ^{\prime}=\frac{R}{4}$.
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