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प्रश्न
A 10 m long wire of a particular material is of resistance 5Ω What will be the resistance if the wire is stretched to double its length?
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उत्तर
On stretching the wire to double its length, the length is doubled and its area of cross-section is reduced to half. So the resistance becomes four times i.e. the resistance of wire will become: 4 × 5Ω = 20 Ω.
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