Two conductors are made of the same material and have the same length. Conductor A is a solid wire of a diameter of 1 mm. Conductor B is a hollow tube of outer diameter 2 mm and inner diameter 1 mm. Find the ratio of resistance RA to RB.

Hint: The resistance of the wire depends on the dimensions of the wire.
Step 1: The resistance of the first conductor;
RA=ρlπ(103×0.5)2

Step 2: The resistance of the second conductor;
RB=ρlπ[(103)2(0.5×103)2]

Step 3: Now, the ratio of two resistors is given by;
RARB=(103)2(0.5×103)2(0.5×103)2=3:1