Posted by Beth on .
Two wires have the same length and the same resistance but are made up of different materials. The resistivities of these materials are 3.97 Ù and 1.97 Ù. Obtain the ratio of the smaller cross-sectional area to the greater cross-sectional area.
Resistance R = r1* l/a1 = r2*l/a2 where r1 & r2 are resistivies of two wires.
So a1/a2 = r1/r2