1. R/n 2. n²R 3. R/n² 4. nR

The resistance of a wire is 'R' ohm. If it is melted and stretched to 'n' times its original length, its new resistance will be :

1. \(\frac{R}{n}\)

2. \(n^2R\)

3. \(\frac{R}{n^2}\)

4. \(nR\)

Doubtly Asked 30 Oct 2026 NEET UG 2017 Practice test neet Save WhatsApp Report

Best answer

Answer: 2. \(n^2R\)

Key idea: melting does not change the volume, so \(Al\) stays constant.

If length becomes \(nl\), area becomes \(A/n\). Resistance \(R=\rho\dfrac{l}{A}\) becomes \(R'=\rho\dfrac{nl}{A/n}=n^2R\).

Doubtly AI · 30 Oct 2026 AI-generated · not yet verified Report

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