A current `I` flows through a cylindrical rod of uniform cross-section area `A` and resistivity `rho`. The electric flux through the shaded cross-section of the rod as shown in figure is

Options

A. `(I)/(rho)`
B. `rho l`
C. `(rho l)/(A)`
D. `(rho A)/(I)`

Answer

B

Explanation

(b) The current density `J`, electric field `E` at the cross-section are related by `J = (E)/(rho)`
Multiplying both side by `A`.
`JA = (EA)/(rho)` or `I = (phi)/(rho)` where `phi` is electric flux.
`or `phi = rho I`