If along a uniform rod of length `l` carrying current `i` the voltage V changes with position x along the length of the rod such that `(dV)/(dx)=-k` where k is a positive number then the resistance of the rod is

Options

A. `kl//2I`
B. `kl//I`
C. `I//kl`
D. `klI`

Answer

B

Explanation

`dV=-IdR-Irho(dx)/A`
`(dV)/(dx)=-I(rho)/A=-k`
`impliesR=kl//I`
II Method:
`V_(2)_V_(1)=int((dV)/(dl))dl=kL=IR`