Question

There are two wire of same length and of the same material and radii r and 2r . The ratio of their specific resistance is?

Answer 1

given

length1=length2=

R1=r

R2=2r

Pl/a/Pl/a=A/A

=pi r(r)/pi2r(2r)=1/2

the required ratio is 1:2

i hope this helps you