Electric resistance

Increase in length is 1.2 times the original, but volume remains constant So apply volume equivalence , you will get new radius in terms of L, now put it in resistance formula, and you will find out 44% increase i. Resistance

R is proportional to l square so if l is increase by 20% Then l2 =6/5 l1 so r2/r1 = square of l2/l1 by solving we Get resistance increase by 44%