A long cylindrical conductor of cross-sectional area A and radius a is made of material whose resistivity depends only on a distance r from the axis of conductor, given by `rho = c/r^(2)`, where c is a constant. Find the resistance per unit length of the conductor and the electric field strength due to which a current I flows in it.

Options

A. `R = (4alphal)/(pia^(3))`
B. `R = (2alphal)/(pia^(4))`
C. `R = (4alpha)/(pila^(3))`
D. `R = (2l)/(pialphaa^(3))`

Answer

B