Question

The resistivity of steel wire is $1\times {10}^{-7}\Omega -m$. The resistance of a steel wire of particular length and thickness is $1\Omega$. If the length and the diameter of the wire both are doubled, then the resistivity in $\Omega -m$ will be

• A. $1\times {10}^{-7}$
• B. $2\times {10}^{-7}$
• C. $4\times {10}^{-7}$
• D. $8\times {10}^{-7}$

Answer 1

Answer: (A)

$1\times {10}^{-7}$

Resistivity of wire depends only on its material and does not change in length and diameter
Hence $\rho =1\times {10}^{-7}\Omega -m$