Answer:
Explanation:
initial length of the wire = l
initial area of crossetion of wire = A
initial resistance of the wire = R
Let the final resistance is r' area is A' and length is l' . Let be the resistivity of the material of the wire.
l' = 3l
So, volume of the wire is constant.
l x A = l' x A'
l x A = 3l x A'
A' = A/3
The resistance of the wire is given by
... (1)
now the new resistance is R'

.... (2)
divide equation (2) by equation (1)
R' = 9 R
Thus, the resistance of wire becomes 9 times.