The resistance of a wire is R. It is bent at | vedclass

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(C) The resistance of a wire is given by $R = \rho \frac{l}{A}$,where $\rho$ is the resistivity,$l$ is the length,and $A$ is the cross-sectional area.

Vedclass · Accepted Answer

$R / 4$

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(C) The resistance of a wire is given by $R = \rho \frac{l}{A}$,where $\rho$ is the resistivity,$l$ is the length,and $A$ is the cross-sectional area.When the wire is bent at the middle by $180^{\circ}$ and the ends are twisted together,the length of the new wire becomes $l' = \frac{l}{2}$.Since the two halves are placed side-by-side,the cross-sectional area of the new wire becomes $A' = 2A$.The new resistance $R'$ is given by $R' = \rho \frac{l'}{A'} = \rho \frac{l/2}{2A} = \frac{1}{4} \left( \rho \frac{l}{A} \right)$.Therefore,$R' = \frac{R}{4}$.

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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