Question

A wire of resistance $5\Omega$ is drawn out so that its length is increased to twice its original length. Calculate its new resistance and resistivity.

Answer 1

we have $R=\frac{\rho L}{A}$ if we increase the length the resistance is also increase

In this case length become 2L so $R_1=\frac{\rho 2L}{A}=2R$

$R=5\Omega$

$\Rightarrow R_1=2\times 5=10\Omega$

new resistance is $10\Omega$ ,resistivity is constant it is a matrial property