Question

If the length of a wire is doubled and its cross – section area decreased to half ,the resistivity of the wire becomes
a)the same
b)four time
c)half
d)one fourth
e)double

Answer 1

Wire resistance is proportional to
(Length)/(Area).

You figure it out. L becomes 2L.
A becomes A/2

2L/(A/2) = 4 L/A

Answer 2

Half