Question

18. What happens to the resistance and resistivity of a wire is the following cases.

i) Wire is cut into two equal halves.

ii) Wire is stretched to double its length.​

Answer 1

In case 1,

resistivity is constant and resistance is half.

In case 2,

resistance is constant and resistivity is half.

Answer 2

Answer:

Explanation:

i) Resistance is directly proportional to length. Since length decreased by half, Resistance also becomes half. Resistivty not change as it a constant and depends on nature of material.
From The Formula R=ρ L/A where
R is restance
ρ​ is resistivity
L is length
A is area of crossection​
ii)  Resistance is directly proportional to length. Since length increase by 2 times, Resistance also becomes increased by 2 times. Resistivty not change as it a constant and depends on nature of material