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Resistance of a wire is r ohms. The wire is stretched to double its length, then its resistance is ohms is?

Resistance of a wire is r ohms. The wire is stretched to double its length, then its resistance is ohms is?

Explanation

When a wire is stretched to double its length, its resistance becomes:

R' = ρ × (2L) / (A/2) = 4 × R

So, the new resistance is 4r ohms