current electricity

Question

a constant current I in a strip line conductor ,resistivity of which increases monotonically in the direction of the current flow.if resistivities at cross sections A and B are ra and rb ,the excess charge accumulated in the section AB is

Answer 1

ρA∫ρB dρ = ρ]ρBρA

ρ = ρ_B - ρ_A

J = I/A

∴ E/ρ = I/A

\(\frac{Q}{4\pi\varepsilon_0.r^2-\rho}\) = I/A

Q = ɛ₀.4πr².ρ.\(\frac{I}{4\pi r^2}\) = ɛ₀(ρ_B - ρ_A) I.