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Physics · PYQ NEET UG 2017
हिन्दीThe resistance of a wire is \( R \) ohm. If it is melted and stretched to \( n \) times its original length, its new resistance will be:-
Correct answer · Option 2
\( n^2R \)
Explanation
Resistance \( R = \rho \frac{l}{A} \). Since volume remains constant when stretched, \( R \propto l^2 \). Thus, new resistance \( R' = n^2 R \).
