Question

Two conductors are made of the same material and have the same length. Conductor

A is a solid wire of diameter 1 mm. Conductor B is a hollow tube of outer diameter

2 mm and inner diameter 1 mm. The ratio of resistance RA to RB is .......... .​

Answer 1

3:1

Explanation:

as we know

R=p×1/A

then

RA/RB = AB/AA=2^2-1^2/1^2

=3