question_answer

A copper wire is stretcher! to make it \[0.5\,%\] longer. The percentage change m in its electrical resistance if its volume remain unchanged is: [JEE Main 09-Jan-2019 Morning]

A) \[0.5\text{ }%\]

B) \[2.5\text{ }%\]

C) \[2.0\text{ }%\]

D) \[1.0\text{ }%\]

Correct Answer: D

Solution :

[d]

Al = constant

So,

option