Question

resistivity of a wire of length L is rho(p) resistivity of a wire of length 2L will be​

Answer 1

2rho(p) will be resistivity of a wire length 2l

Answer 2

so

R_1 =$p\frac{l}{a}$

since if the same wire is stretched and doubled then the volume would be same and area of cross section will be halved

$R_2 = p\frac{2L}{\frac{A}{2}}$

$R_2 = 4p\frac{L}{A}$

$\frac{R_2}{R_1} = \frac{p\frac{l}{a}}{4p\frac{L}{A}}$

$R_2 = 4R_1$