Question

6. The radius of a conducting wire is doubled. What will be the ratio of its new specific resistance (resistivity) to the old one?

Answer 1

The specific resistance will be 4 times the original. As resistivity increases with the increase in length of the wire.

Answer 2

1:4
the specific resitance is directly proportional to Area of cross section of wire
(pi×r^2)
rho=A×R/L

keeping length constant radius has doubled
hence
Specific resistance will become four times the original