SI unit of resistivity is

(a) Define resistivity. Write an expression for the resistivity of a substance. Give the meaning of each symbol which occurs in it. (b) State the SI unit of resistivity. (c) Distinguish between resistance and resistivity. (d) Name two factors on which the resistivity of a substance depends and two factors on which it does not depend. (e) The resistance of a metal wire of length 1m is 26 Omega at 20^(@)C . if the diameter of the wire is 0.3mm, what will be the resistivity of the metal at that temperature?

These question consist of two statements each, printed as Assertion and Reason. While answering these questions you are required to choose any one of the following four responses : The resistivity for a substance is its resistance when it is one meteer ling and its area of crosss section is one square meter. The SI units of resistivity are ohm metre Omegam and ohm centimeter Omega cm .