There are two wires of the same length and of the same material and radii $r$ and $2r$ . The ratio of their specific resistance is
A$1 : 2$
B$1 : 1$
C$1 : 4$
D$4 : 1$
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B$1 : 1$
b The resistivity or specific resistance of a material is an intensive property and it is defined as a resistance offered by a unit length and unit cross section area of that material when a fixed voltage is applied across it. so the specific resistance only depends upon temperature and material not on physical properties like size and shape.
Hence $B$ is correct option.
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