Three copper wires of lengths and cross sectional areas are l- A 2l- A2 and l2- 2A- Resistance is minimum in

The correct option is C wire of cross sectional area 2A We know that , R ∝l/A ;So, the resistance of the wire will be minimum when the area of cross ...

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Standard IX

Physics

Resistance

Three copper ...

Question

Three copper wires of lengths and cross sectional areas are $(l, A) (2 l, \frac{A}{2})$ and $(\frac{l}{2}, 2 A)$ . Resistance is minimum in

wire of cross-sectional area

\frac{A}{2}

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wire of cross-sectional area

A

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wire of cross-sectional area

2 A

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same in all the three cases

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Solution

The correct option is C wire of cross-sectional area $2 A$
We know that , $R \propto \frac{l}{A}$ ;
So, the resistance of the wire will be minimum when the area of cross-section is maximum and length is minimum.the wire of cross-sectional area have maximum area and minimum length hence it will have minimum resistance out of all other combinations.

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Similar questions

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Three copper wires of lengths and cross sectional areas are (l, A) (2l, A2) and (l2, 2A). Resistance is minimum in

Three copper wires of lengths and cross sectional areas are $(l, A) (2 l, \frac{A}{2})$ and $(\frac{l}{2}, 2 A)$ . Resistance is minimum in