Two wires of the same material and same length have radii 1 mm and 2 mm respectively. Compare (i) their resistances, (ii) their specific resistance.
(i) Resistance is inversely proportional to cross-sectional area.
R1R2=A2A1=πr22πr21=2212=4:1
(ii) As they are made up of the same material, their specific resistances are the same.