A copper wire of resistance $ 4\Omega$ is melted and redrawn to thrice its original length. The resistance of stretched wire is
Answer & explanation
Correct answer: option 3
$ R'= \frac{l'2}{l^2} R = 9\times 4\Omega = 36\Omega$
A copper wire of resistance $ 4\Omega$ is melted and redrawn to thrice its original length. The resistance of stretched wire is
Correct answer: option 3
$ R'= \frac{l'2}{l^2} R = 9\times 4\Omega = 36\Omega$