(a) Define the resistivity of a conductor. Write its SI unit.
(b) What happens to the specific resistance of a conductor when a) its length is doubled? b) its radius is halved? Justify your answer.
(a) Resistivity is defined as rho = RAl, where R is the resistance, A is the cross-sectional area, and l is the length. SI unit: ohm-meter (Ω·m).
(b) a) The specific resistance will be doubled. b) The specific resistance will be halved.