The resistance of two wires X and Y are in the ratio of 2 : 1, their lengths are in the ratio 1 : 2 and their diameters are also in the ratio of 1 : 2.
What is the ratio of the resistivities of wires X and Y?
A 1:2 B 1:1 C 2:1 D 4:1
Solutions: Option B
Note that when the diameter of the wire doubles, the cross-sectional area increases by 4 times.
Comparing the resistances of both X and Y as shown below, the ratio of resistivities is 1:1.