Two copper wires of lengths l and 2l have radii r and 2r respectively. what is ratio of their specific resistance ?

Question

Two copper wires of lengths l and 2l have radii r and 2r respectively. what is ratio of their specific resistance ? (A)  1: 2  (B)  2: 1  (C)  1: 1  (D)  1: 3

Tardigrade Admin · Accepted Answer

The specific resistance (ρ) is the characteristic of the material of conductor. Its value depends only on the material of conductor and its temperature. Its value does not depend on the length and area of cross-section of the conductor. If a wire is stretched or doubled on itself, its resistance will change, but its specific resistance will remain unaffected. More conducting the substance, less is its specific resistance.

Q. Two copper wires of lengths $l$ and $2 l$ have radii $r$ and $2 r$ respectively. what is ratio of their specific resistance ?

$1 : 2$

$2 : 1$

$1 : 1$

$1 : 3$

Q. Two copper wires of lengths l and 2l have radii r and 2r respectively. what is ratio of their specific resistance ?

1:2

2:1

1:1

1:3

Q. Two copper wires of lengths $l$ and $2 l$ have radii $r$ and $2 r$ respectively. what is ratio of their specific resistance ?

$1 : 2$

$2 : 1$

$1 : 1$

$1 : 3$