Question

Write the relation between resistance and electrical resistivity of the material of a conductor in the shape of a cylinder of length `'l'`  and area of cross-section `'A'` . Hence derive the S.I. unit of electrical resistivity.

Answer 1

`R = (rho l)/A` 

δ = Electrical resistivity 

A = cross sectional area. 

l =  length of cylindrical wire.

unit of `rho = (RA)/l`  = `(Omegam^2)/m` = `Omega` - m